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VETERINARY  MEDICINE  SERIES 

No.  4 


SWINE  DISEASES 

BY 

A.  T.  KINSLEY,  M.  Sc,  D.  V.  S. 


ILLUSTRATED 


Chicago 

AMERICAN  JOURNAL  OF  VETERINARY  MEDICINE 

1914 


Copyright  1914 

By 
D.  M.  Campbkll 


PREFACE 


The  experience  of  the  writer  in  teaching,  and 
in  the  manufactui*e  and  distribution  of  anti-hog 
cholera  serum,  no  less  than  in  practice,  has 
forcibly  impressed  upon  him  the  need  of  the 
veterinary  profession  for  more  general  knowl- 
edge of  the  diseases  of  swine. 

They  are  not  few  who  maintain  that  vet- 
erinary practice  in  the  future  will  be  concerned 
largely  with  the  food-producing  animals.  The 
automobile  has  already  supplanted  most  of  the 
fancy  driving  horses;  the  auto-truck  does  much 
that  would  otherwise  be  accomplished  bj^ 
horses;  and  predictions  are  rife  that  the  gaso- 
lene tractor  will  soon  be  made  practicable  for 
work  on  small  farms.  All  things  considered  it 
seems  probable  that  the  equine  population  of 
the  country  is  destined  to  increase  but  slowly  if 
at  all.  The  keeping  of  pet  animals,  including 
dogs  and  cats,  is  being  looked  upon  more  and 
more  as  an  insanitary  practice,  while  the  farm 
dog  and  the  roaming  cur  are  becoming  more 
and  more  the  object  of  antagonistic  legislation. 
Contrasted  with  the  foregoing,  the  increasing 
price  of  meat  food  products  makes  it  seem  de- 
sirable that  veterinarians  in  general  better  equip 
themselves  for  the  treatment  of  the  ailments  of 
food  producing  animals  and  thus  qualif}"  them- 
selves to  render  greater  service  to  the  public  in 


a  line  of  practice  that  is  not  likely  to  be  affected 
by  progress  and  invention. 

It  is  the  aim  of  this  work  to  supply  this  in- 
formation in  a  compact,  readily  assimilated 
form  for  both  students  and  practitioners.  Ac- 
knowledgement must  be  made  to  Dr.  D.  M. 
Campbell,  editor  of  the  American  Journal  of 
Veterinary  Medicine  for  the  illustrations 
used  herein,  and  he  washes  me  to,  in  turn, 
acknowledge  his  indebtedness  to  Dr.  L.  Enos 
Day,  in  charge  of  the  Branch  Pathological 
Laboratory  of  the  Bureau  of  Animal  Industry 
of  Chicago,  and  his  assistant  Dr.  G.  Tinsley 
Creech,  for  permission  to  photograph  a  nimiber 
of  specimens  in  the  very  excellent  museimi 
maintained  in  connection  with  their  laboratory. 
And  also  indebtedness  to  the  American 
Serum  Company  of  Kansas  City  for  photographs 
of  their  plant  used  in  illustrating  the  manu- 
facture of  anti-hog  cholera  serum. 

A.  T.  Kinsley. 

Kansas  City,  December  1914. 


CONTENTS 

SECTION  I.  PAGE 

The  Digestive  System 9 

Lips;  Malformations  —  Cheilitis  —  Tumors.  Tongue; 
Glossitis^Tumors — Parasites.  Mouth;  Stomatitis — Scur- 
vy— Parotiditis — Tonsillitis.  Pharynx;  Pharyngitis — 
Pharyngeal  Paralysis — Tumors.  Esophagus;  Malforma- 
tions —  Stenosis  —  Dilatation —  Perforation  —  Esophagitis 
— Tumors.  Stomach;  Malformations — Foreign  Bodies — 
Emesis — Anemia — Hematamesis — Peptic  Ulcers— Hyper- 
emia— Gastritis — Dilatation — Tumors — Parasites.  Intes- 
tines; Malformations — Entorrhagia — Obstruction — Dila- 
tations— Emphysema — Enteritis — Toxic  Gastritis,  Gastro- 
enteritis, Enteritis — Scours  in  Sucklings — Parasites  — 
Tumors.  Liver;  Malformations — Foreign  Bodies — Rup- 
ture— Icterus — Cloudy  Swelling — Fatty  Changes — Amy- 
loid Changes — Glycogenic  Infiltration — Cholelithiasis — 
Hyperemia — ^Hepatitis — Tumors — Parasites.  Pancreas; 
Peritoneum;  Injuries  —  Ascites  —  Peiitonitis  —Tumors — 
Parasites. 

SECTION  II. 

The  Respiratory  System 75 

Nose;  Epistaxis — Rhinitis — Infectious  Nasal  Catarrh — 
Tumors.  Larynx;  Laryngitis — Tumors.  Trachea;  Mal- 
formations—  Stenosis — Tracheitis — Tumors.  Bronchial 
Tubes;  Stenosis  —  Bronchitis  —  Verminous  Bronchitis 
and  Pneumonia.  Lungs;  Atelectasis — Emphysema — 
Edema — Hemorrhage — Pneumonia — Tumors — Parasites . 
Pleura;  Hydrothorax — Hemothorax — Pneumothorax — 
Pleurisy — Tumors . 

SECTION  III. 

The  Uro-Genital  System 99 

Kidneys;  Malformations  —  Hydronephrosis  —  Hemor- 
rhage— Fatty  Changes — Calculi — Congestion — Nephritis 
—Pyelonephritis— Albuminuria— Uremia — Tumors — Par- 
asites. Ureters;  Malformations.  Bladder;  Malforma- 
tions— Hematuria — Dilatation^  Calculi — Cystitis — Tum- 
ors. Urethra;  Stricture — Urethritis.  Prostate-Gland: 
Cowper's  Glands:  Testicles;  Orchitis  and  Epididymitis — 
Tumors.  Seq^^els  to  Castration;  Hemorrhage — Infection — 
Botryomycosis — Actinomycosis — Parasites — Scrotal  Her- 
nia. Penis:  Ovary;  Malformations — Hemorrhage — Ooph- 
oritis— Cysts — Tumors.  Fallo]nan  Tubes:  Uterus;  Mal- 
formations—Injuries— Hemorrhage — Metritis  —  Tumors. 
Vagina:  Vulva:  Mammary  Glands;  Mammitis — 
Botryomycotic  Mammitis — Actinomycotic  Mammitis — 
Tuberculous  Mammitis— Tumors. 

.5 


CONTENTS— Continued 


SECTION  IV. 

Organs  of  Locomotion 135 

Sore  Feet — Fatty  Degeneration — Muscular  Rheumatism 
—Articular  Rheumatism — Rachitis— Osteomalatia — Puru- 
lent Osteomyelitis — Trichinosis — Cysticercosis  (measles) 
— Sarcosporidiosis — Tumors . 

SECTION  V. 

The  Skin 149 

Erythema— Sunburning — Freezing — Hemorrhage — Urti- 
caria— Eczema — Dermatitis  Granulosa — Necrobacillosis — 
Actinomycosis — Tumors — Parasites. 

SECTION  VI. 
Circulatory  Organs 159 

Heart;  Pericarditis — Hemorrhage — Fatty  Changes— En- 
docarditis— Tumors — Parasites.  Blood  Vessels:  Blood; 
Anemia — Leukemia.  Spleen;  Necrosis — Hyperthrophy 
— Sarcomatosis. 

SECTION  VII. 

The  Nervous  System 163 

Malformations — Delirium — Viciousness — ^Sunstroke — 
Heat  Stroke — Lightning  Stroke  —  Epilepsy  —  Dentition 
Eclampsia — Chorea— Cerebral  Hyperemia — Parasites. 

SECTION  VIII. 

Infectious  Diseases 169 

Hog  Cholera;  History — Extent— Etiology— Sources  of 
Infection — Manner  of  Infection — Susceptibihty — Chan- 
nels of  Infection — Period  of  Incubation — Lesions— Symp- 
tons — Diagnosis— Prognosis —  Treatment  — Preventative 
Treatment — Anti-Hog  Cholera  Serum — Manufacture  and 
Use.  Sivine  Plague:  Necrobacillosis;  Necrotic  Stomati- 
tis— Necrotic  Enteritis — Necrotic  Rhinitis — Necrotic 
Pneumonia — Necrotic  Hepatitis — Necrosis  of  the  Spleen— 
Vaginal,  Vulvar  and  Preputial  Necrobacillosis — Necro- 
bacillosis of  the  Skin— Other  Forms  of  Necrobacillosis. 
Tuberculosis:  Pyemic  Arthritis;  Spasms  of  the  Diaphragm: 
Raines;  Fool  and  Mouth  Disease. 


ILLUSTRATIONS 


FIGURE  PAGE 

.1 .      Glossitis 11 

2.  Ascaris  Suum 48 

3.  Gigantorhynchus  Hirudinaceus 52 

4.  Adeno-Sarcoma  of  the  Kidney Ill 

5.  Actinomycosis 1*. 121 

6.  Scirrhous  Cord  due  to  Botryomycotic  Infection 122 

7.  Infection  of  the  Udder 131 

8.  Cysticercosis  (Pork  Measles) 145 

9.  Pedunculated  Fibroma 146 

10.  Elephantiasis 152 

11.  Mucous  Membrane  of  the  Bladder 177 

12.  Mucous  Membrane  of  the  Intestine 179 

13.  Hearts 181 

14.  Early  Stages  of  Hog  Cholera 183 

15.  Acute  Hog  Cholera,  Advanced  Stage 185 

16.  Heart  Showing  Hemorrhages  due  to  Hog  Cholera 187 

17.  Kidneys 188 

18.  Lymph  Nodes 189 

19.  Virus  Bleeding  Room 194 

20.  Hyperimmunizing  Room 196 

21.  Serum  Centrifuging  Room 200 

22.  Sterihzing  Room 201 

23.  Cholera-Immune  Hogs 203 

24.  Necrobacillosis 212 

25.  Fat  Necrosis 215 

26.  Tuberculosis  of  the  Tongue 221 

27.  Tuberculosis  of  the  Skin .222 

28.  Tuberculosis  of  the  Pleura 225 

7 


COLOR  PLATES 


PLATE      1 0pp.  p.  182 

Fig.  1.    Skin  Lesions  of  Hog  Cholera. 
Fig.  2.    Intestinal  Lesions  of  Hog  Cholera. 

PLATE     II 0pp.  p.  198 

Fig.  L    Thrombosis  of  the  Liver. 

Fig.  2,    Pulmonary  Lesions  of  Hog  Cholera. 

PLATE  III 0pp.  p.  218 

Fig.  L    Hepatic  Lesions  of  Tuberculosis. 
Fig.  2.     Bone  Lesions  of  Tuberculosis. 

PLATE   IV 0pp.  p.  224 

Fig.  1.     Splenic  Lesions  of  Tuberculosis. 
Fig.  2.    Pulmonary  Lesions  of  Tuberculosis. 


SECTION  I 
THE  DIGESTIVE  SYSTEM 

The  Mouth  a?id  its  Associated  Parts 

THE  mouth  of  swine  is  prone  to  injuries  and  infection 
because  they  are  likely  to  ingest  foods  in  various 
states  of  refinement,  and  not  infrequently  they 
consume  foreign  bodies  that  may  produce  such  injuries 
as  contusions  and  lacerations.  The  comfort  and  health 
of  swine  are  not  always  considered  by  the  feeder,  who  may 
thoughtlessly  give  foods  sufficiently  hot  or  cold  to  produce 
damage  to  the  buccal  mucous  membrane.  Injuries  to 
this  membrane  are  predisposed  to  infection  that  may 
produce  pathologic  conditions  varying  from  simple 
inflammation  to  suppuration  or  even  necrosis. 

LIPS 
Malformations 

Malformations  of  the  lips  of  swine  are  not  rare,  the 
most  frequent  malformation  being  the  condition  popularly 
termed  "hair  lip"  (schistosis  lahii).  This  condition  is 
rarely  observed  in  mature  swine  because  the  defect 
renders  nursing  extremely  difficult  and  frequently  im- 
possible; such  pigs,  therefore,  die  before  they  have  passed 
the  nursing  stage.  Schistosis  labii,  when  not  associated 
with  other  developmental  errors,  is  usually  easily  relieved 
by    operation. 

Cheilitis 

The  lips  are  also  subject  to  injuries  inflicted  by 
rough  foods  or  by  foreign  bodies  in  the  food.  Wounds, 
too,  may  be  inflicted  by  dogs.  Because  of  their  location, 
lip  wounds  are  predisposed  to  infection.  Inflammatory 
processes  of  the  lips  are  usually  confined  to  the  mucous 
surface. 


10  SWINE  DISEASES 

Catarrhal  cheilitis  is  of  rather  common  occurrence, 
particularly  in  small  pigs,  and  may  be  either  acute  or 
chronic.  This  condition  is  usually  caused  by  improper 
food  or  undue  exposure  to  very  dry  atmosphere.  The 
lesions  of  the  acute  type  consist  of  small  crevices  which 
in  extreme  cases  may  bleed  freely.  In  the  chronic  type 
the  cracks  and  crevices  become  more  extensive  and  the 
surrounding  tissues  are  infiltrated  with  varying  quantities 
of  newly  formed  fibrous  tissue.  Catarrhal  cheilitis,  either 
acute  or  chronic,  is  not  a  serious  condition  and  is  usually 
corrected  when  the  cause  is  removed. 

Suppurative  cheilitis  is  occasionally  observed.  It  is 
usually  the  result  of  infection  of  the  subsurface  labial 
tissues  with  pyogenic  bacteria.  The  usual  form  of  this 
type  of  cheilitis  is  circumscribed,  and  the  lesions  are 
similar  to  the  lesions  observed  in  the  usual  abscess 
formation.     This  condition  is  relieved  by  operation. 

Diphtheritic  cheilitis  is  very  prevalent  in  some  sections 
of  the  United  States,  particularly  in  young  pigs.  The 
usual  causative  agent  is  the  Bacillus  necrophorus.  This 
microorganism  produces  a  variety  of  lesions  and  is  of  so 
great  economic  importance  that  all  of  the  disease  pro- 
cesses resulting  from  it  will  be  discussed  under  the  topic, 
"Necrobacillosis,"  in  Section  VIII.  (See  p.  213.) 

Vesicular  cheilitis  has  been  reported  as  occurring  in 
suckling  pigs.  This  condition  is  probably  caused  by  a 
yeast,  the  oidium  albicans.  The  lesions  of  vesicular 
cheilitis  are  practically  confined  to  the  mucous  surfaces 
of  the  lips.  The  mucous  membrane  is  tumefied  and 
scarlet  red  in  color,  and  in  the  beginning  and  later  small, 
sharplj'  circumscribed  vesicles  appear  and  the  mucosa 
becomes  white,  due  to  the  accumulated  desquamated 
epithelium  and  mucus.  The  vesicles  rupture  and  the 
vesicular  membrane  may  slough,  leaving  a  denuded 
surface,  or  the  vesicular  membrane  maj^  collapse  after 
the  discharge  of  its  content  and  appear  as  a  small,  white 
mass  upon  the  mucous  membrane.  This  condition  is 
usually  not  serious,^  although  it  may  cause  considerable 


thp:  digestive  system  ii 

inconvenience  in  sucking.     It  is  usually  relieved  by  the 
topical  application  of  properly  selected  antiseptics. 

Tumors 

Labial  tumors  are  not  of  common  occurrence  in 
swine,  although  fibroma,  myxoma,  and  epithelioma  have 
been  observed. 

TONGUE 

The  tongue  is  also  subject  to  injuries  of  various 
types.  Tongue  injuries  may  be  inflicted  by  improper 
food,  by  foreign  bodies  in  the  food,  or  by  sharp,  irregular 
teeth. 


Fig:.  1.—  GLOSSITIS. 
This  tongue  was  taken  from  an  apparently  normal  hog.     It  contained 
twenty-four  polished  nails  lodged  in  one  place. 

Glossitis 

Inflammatory  disturbances  of  the  tongue  may  involve 
the  mucous  membrane  only  or  the  submucous  muscular 
portion  of  the  tongue.  The  inflammations  of  the  lingual 
mucous  membrane  are  practically  identical  with  those  of 
the  lips  and  will  not  be  given  further  consideration. 
Inflammation  of  the  lingual  musculature  is  usually  the 
sequel  of  an  injury  which  had  provided  an  avenue  of 
entrance  for  infection.  Inflammation  of  the  substructures 
of  the  tongue  may  be  acute  or  chronic,  diffuse  or  cir- 


12  SWINE  DISEASES 

cumscribed,  nonsuppurative  or  suppurative.  Diffuse 
nonsuppurative  subsurface  glossitis  is  usually  acute  and  is 
the  result  of  infection  with  streptococci  or  some  septic 
microorganism.  The  lesions  in  this  type  of  glossitis 
consist  of  a  diffuse,  extensive  tumefaction  of  the  tongue, 
which  on  section  evidences  enlargement  of  the  blood 
vessels  and  abundant  accumulations  of  pus,  or  other 
inflammatory  products,  between  the  muscle  bundles, 
while  the  muscle  tissue  will  have  a  parboiled  appearance. 
Acute  circumscribed  subsurface  suppurative  glossitis  par- 
takes of  the  nature  of  an  abscess.  Chronic  glossitis  is 
most  frequently  diffuse  and  is  exemplified  in  those  cases 
of  diffuse  lingual  actinomycosis.  The  lesions  consist 
primarily  of  an  excessive  quantity  of  fibrous  tissue  which 
may  contract  unequally  in  different  portions  of  the 
tongue,  thus  producing  an  irregularity  of  the  surface  of 
the  organ.  Portions  of  the  tongue  in  which  excessive 
quantities  of  fibrous  tissues  are  developed  become  dense 
and  hard,  and  cut  with  considerable  resistance. 

Tumors 

Lingual  tumors  are  relatively  uncommon,  but  retention 
or  obstruction  cysts  have  been  observed. 

Parasites 

Parasitic  invasion  of  the  tongue  is  not  uncommon. 
The  cystic  form  of  the  Taenia  solium,  that  is,  the 
Cysticercus  cellulosse,  frequently  occurs  in  the  muscular 
portion  of  the  tongue.  The  cystic  form  of  the  Tri- 
chinella  has  also  been  observed  in  lingual  muscles,  while 
psorosperms  occasionally  inhabit  the  muscle  of  the  tongue. 

MOUTH 

The  mucous  membrane  of  the  mouth,  other  than 
that  mentioned  in  relation  to  the  lips  and  tongue,  is 
subject  to  injuries  of  a  similar  origin  and  nature  and 
will  not  be  further  discussed  here. 


THE  DIGESTIVE  SYSTEM  13 

Stomatitis 

Catarrhal  inflamination  of  the  buccal  mucous  mem- 
brane is  relatively  common  and  may  be  local  or  general, 
acute  or  chronic.  Acute  catarrhal  stomatitis  is  usually 
caused  by  the  ingestion  of  improper  food,  although  it 
may  be  associated  with  some  general  infective  disease  or 
be  the  result  of  injury.  The  practice  of  catching  swine 
by  means  of  a  rope  or  wire  over  the  upper  jaw  is  very 
likely  to  produce  injury  to  the  buccal  mucous  membrane. 
The  affected  mucous  membrane  is  in  the  beginning 
tumefied  and  increased  in  redness,  and  later  the  surface 
becomes  coated  by  the  accumulation  of  desquamated 
epithelium  and  mucous.  Gradually  this  surface  coating 
loosens  and  sloughs  as  the  inflammation  diminishes  in 
intensity.  The  affected  animals  refuse  to  eat,  or  eat 
sparingly,  and  usually  select  soft  foods.  Although  they 
may  attempt  to  chew  hard  substances,  as  a  rule  they 
drop  them  quickly  to  the  ground.  Salivation  is  always 
present,  and  in  extreme  cases  an  offensive  odor  may  be 
detected. 

The  treatment  consists  of  cleansing  the  affected  parts 
with  antiseptics  and  applying  an  astringent,  such  as 
myrrh.  The  affected  animals  should  be  given  soft 
foods,  and  a  good  supply  of  clean,  cool  water. 

Chronic  catarrhal  stomatitis  is  caused  by  the  continuous 
or  prolonged  action  of  some  relatively  mild  irritant. 
This  condition  is  associated  with  fibrous  proliferation 
in  the  submucosa  which  in  the  early  stages  of  the  disease 
results  in  tumefaction  of  the  mucosa.  Later  the  newly 
formed  fibrous  tissue  contracts,  producing  an  irregular 
surface.  There  is  also  a  gradual  atrophy  of  the  mucosa 
and  occasionally  the  cicatrized  fibrous  tissue  obstructs 
mucous  gland  ducts,  thereby  causing  small  retention 
cysts. 

Chronic  catarrhal  stomatitis  is  manifested  by  con- 
tinuous limited  salivation  and  champing  of  the  jaws. 
The  treatment  depends  largely  upon  the  progress  of  the 
disease.     In  all  cases  the  cause  should  be  determined 


14  SWINE  DISEASES 

and  removed.  Soft  foods  should  be  given,  and  mild 
astringent  antiseptic  washes  may  be  used. 

Phlegmonous  stomatitis  is  relatively  common  in  swine. 
It  is  usually  caused  by  a  streptococcic  infection  of  the 
submucosa.  The  condition  is  usually  general,  the 
affected  mucosa  is  intensely  swollen  and  in  the  beginning 
is  scarlet  red  in  color,  later  assuming  a  purplish  hue,  and 
finally  a  dull  gray  color  due  to  the  accumulation  of 
desquamated  epithelium,  mucous,  and  pus.  Patches  of 
mucous  membrane  may  become  necrotic  and  slough, 
leaving  a  red  surface  from  which  blood  escapes  freely. 
The  tumefaction  may  be  so  intense  that  the  mouth 
cavity  becomes  noticeably  diminished,  and  the  cheek 
mucous  membrane  may  be  forced  between  the  teeth 
and  lacerated  during  mastication. 

The  affected  animals  refuse  to  eat,  and  although  they 
frequent  the  drinking  trough,  they  will  actually  drink 
very  little.  There  will  be  a  frothy,  ill-smelling  discharge 
from  the  mouth.  There  may  be  a  rise  of  from  one  to 
three  degrees  Fahrenheit  in  temperature.  The  treatment 
consists  of  mouth  washes  of  antiseptics,  frequently 
apphed. 

Vesicular  ulcerative  stomatitis  is  caused  by  the  same 
agencies  and  presents  lesions  similar  to  vesicular  cheilitis, 
and  will  not  be  further, discussed. 

Diphtheritic  stomatitis  is  not  uncommon,  particularly 
in  suckling  pigs.  The  further  discussion  of  this  condition 
will  be  found  under  the  topic,  "Necrobacillosis,"  in 
Section  VIII.  (See  p.  216) 

Symptoms. — As  above  indicated,  the  symptoms  of 
stomatitis  of  the  various  types  vary  only  in  intensity. 
There  is  more  or  less  of  salivation  and  drooling,  champing 
of  the  jaw^s,  and  evidence  of  difficulty  in  mastication.  On 
inspection  the  lesions  will  be  evident,  w^hich  are  usually 
sufficient  upon  which  to  base  a  diagnosis. 

Treatment. — The  treatment  also  will  vary  with  the 
type  of  inflammation.  In  all  instances  the  cause  should 
be  removed,  and  in  the  infectious  types  there  should  be 
topical  application  of  some  suitable  antiseptic. 


THE  DIGESTIVE  SYSTEM  15 

Scurvy 

This  is  a  disease  manifested  by  ulceration  and  hemor- 
rhage of  the  gums,  unthriftiness,  and  debility.  It  is  of 
rather  common  occurrence  in  young  pigs. 

Etiology. — There  appears  to  be  no  specific  exciting 
cause  of  this  condition.  However,  it  usually  occurs  in 
pigs  that  are  improperly  fed,  kept  in  unsanitary  quarters, 
or  those  produced  from  continued  inbreeding. 

Lesions. — Scurvy  is  characterized  by  progressive 
ulceration  of  the  gums.  These  ulcers  are  irregular, 
ragged,  and  bleed  almost  constantly.  Petechial  hemor- 
rhages may  be  found  in  the  skin,  and  in  the  mucous 
and  serous  membranes.  The  liver  and  kidneys  may 
show  fatty  changes.  The  spleen  and  lymph  nodes  are 
enlarged. 

Symptoms. — Progressive  emaciation,  dullness,  dimin- 
ished appetite,  increased  thirst,  and  a  dislike  to  move 
characterize  scurvy.  On  inspection,  the  gum  ulcerations 
will  be  observed,  and  there  may  also  be  cutaneous  hemor- 
rhages visible.  The  disease  is  rather  serious  unless  the 
cases  are  observed  early. 

Parotitis — Parotiditis 

Parotitis  is  rare  in  swine.  In  The  American  Veterinary 
Revieio  (Vol.  43,  p.  298),  Kaupp  reported  three  fatal 
cases.  It  appears  from  the  report  that  two  dogs  also  ^ 
contracted  the  disease.  This  condition  is  usually  not 
serious,  and  when  the  conditions  associated  with  it  are 
relieved  the  lesions  rapidly  disappear. 

Tonsillitis 

The  tonsillar  tissue  of  swine  is  prone  to  either  acute 
or  chronic  inflammation.  Acute  tonsillitis  is  closely 
associated  with  acute  pharyngitis,  and  the  cause  is 
probably  most  frequently  infectious  in  character.  The 
tonsillar  tissue  becomes  tumefied  and  projects  above  the 
surface,  while  the  buccal  mucous  membrane  is  hot  and 
red.     The  affected  animals  are  indisposed  and  dull,  and 


16  SWINE  DISEASES 

have  a  tendency  to  extend  the  head  and  elevate  the 
snout.  There  is  usually  a  rise  of  temperature.  Deglu- 
tition is  difficult  and  may  be  associated  with  gagging 
and  sometimes  with  vomition.  There  may  be  spasmodic 
coughing. 

The  treatment  consists,  in  the  mild  cases,  in  applying 
soothing  astringents;  in  the  more  severe  cases,  tincture 
of  iron  chlorid  may  be  used.  Laxatives  should  be  given 
to  keep  the  bowels  in  an  active  state,  and  the  animals 
should  be  placed  in  clean,  well-ventilated  quarters,  and 
given  liquid  and  easily  digested  foods. 

Chronic  tonsillitis  is  less  common  than  the  acute 
form.  It  is  characterized  by  distention  of  the  tonsillar 
tissue  by  accumulated  desiccated  pus  or  even  calcareous 
masses  in  the  tonsillar  crypts. 

PHARYNX 

The  pharynx,  like  the  mouth,  is  subject  to  trauma- 
tisms and  infection. 

Pharyngitis 

Catarrhal  pharyngitis  is  the  most  common  type  of 
inflammation,  and  may  be  either  acute  or  chronic.  The 
usual  cause  of  the  disease  is  improper  food  or  undue 
exposure,  although  it  may  be  caused  by  infection. 

The  mucous  membrane  of  the  pharynx  affected  with 
acute  catarrh  is  in  the  beginning  dry  and  scarlet  red, 
later  becoming  tumefied  and  coated  with  epithelium 
and  mucous,  which  occasionally  desquamates,  leaving 
denuded  areas. 

If  the  causative  agent  persists  the  condition  becomes 
chronic.  The  chronic  condition  is  evidenced  by  fibrous 
proliferation  in  the  submucosa  resulting,  first,  in  a 
tumefaction,  and  then  in  protrusion  of  the  pharyngeal 
mucosa,  which  may,  by  contraction  of  the  newly  formed 
fibrous  tissues,  result  in  a  corrugation  of  the  mucous 
membrane,  or  the  newly  formed  fibrous  tissues  may  be 
so  extensive  that  the  pharyngeal  mucosa  becomes  uni- 


THE  DIGESTIVE  SYSTEM  17 

formly  tumefied,  dense  and  hard.  In  either  case  the 
epithelium  of  the  mucous  membrane  becomes  atrophied, 
leaving  only  a  thin  covering,  usually  of  a  squamous 
type  of  epithelium. 

Phlegmonous  pharyngitis  is  not  infrequently  associated 
with  phlegmonous  stomatitis,  although  it  may  occur 
independently.  Streptococci  are  the  usual  cause  of 
phlegmonous  pharyngitis,  and  the  lesions  are  practically 
identical  with  those  of  phlegmonous  stomatitis. 

Diphtheritic  pharyngitis  is  not  rare  in  swine.  It  is 
the  result  of  the  Bacillus  necrophorus,  and  practically 
the  same  lesions  are  observed  as  in  necrobacillosis. 

Paralysis 

Paralysis  of  the  pharynx  is  a  condition  resulting 
from  disturbances  of  the  controlling  pharyngeal  nerves 
or  of  the  muscles  of  the  pharynx.  This  condition  is 
usually  associated  with  rabies,  although  it  has  been 
observed  independent  of  that  disease  and  probably 
resulted  from  the  influences  of  some  substance  upon  the 
deglutition  centers  of  the  medulla. 

Tumors 

Pharyngeal  tumors  in  swine  are  not  very  common. 
Occasionally  polypoid  fibromas  are  observed,  but  they 
are  rare.  Of  the  malignant  tumors  the  epitheliomas 
are  most  often  met  with;  however,  these  are  rare. 
Adenomas  and  carcinomas  also  have  been  observed,  but 
infrequently, 

ESOPHAGUS 

Malformations 

Malformations  of  the  esophagus  are  rather  rare. 
The  canal  may  end  abruptly  at  the  lower  end  of  the 
upper  third,  beginning  lower  down,  and  continue  to  the 
stomach,  or  the  esophagus  may  form  a  union  with  the 
trachea.  In  rare  instances  fistulous  openings  have  been 
observed  in  the  cervical  region. 


18  SWINE  DISEASES 

Stenosis 

Stenosis,  or  narrowing  of  the  esophagus,  is  not  infre- 
quent. This  condition  occurs  most  frequently  at  the 
pharyngo-esophageal  junction  or  at  the  cardiac  termina- 
tion, the  cause  being  either  extrinsic  or  intrinsic. 

Etiology. — Among  extrinsic  causes  may  be  pressure 
from  enlarged  thyroids,  tumors,  aneurysms,  or  abscesses. 
Foreign  bodies,  too,  often  produce  partial  obstructions 
of  the  esophagus,  thus  causing  a  temporary  stenosis. 
The  intrinsic  causes  are  most  frequently  due  to  scars 
or  scar  tissues  that  have  formed  as  a  result  of  injuries 
or  of  diseased  processes  of  the  esophageal  tissues. 
Hj^perpiasia  of  the  esophageal  muscle,  also,  may  pro- 
duce stenosis. 

Lesions. — The  usual  anatomical  changes  observed 
in  esophageal  stenosis  consist  of  cicatrized  fibrous  tissues. 
The  extent  of  the  trouble  varies,  but  as  a  rule  it  involves 
only  a  small  portion  of  the  esophagus.  The  stenosis 
may  form  a  regular  or  irregular  diminished  lumen. 

Symptoms. — The  symptoms  evidenced  in  esophageal 
stenosis  consist  of  difficult  deglutition  and  sometimes 
dilatation  (which  see),  succeeded  by  the  formation  of 
jabot,  which  may  be  observed  in  animals  thin  in  flesh. 

Treatment. — Surgical  interference,  which  may  or 
may  not  be  successful,  depending  upon  the  extent  of  the 
lesions  and  the  age  of  the  animal  involved,  is  the  only 
treatment  for  esophageal  stenosis. 

Dilatation 

Esophageal  dilatation  is  less  frequently  met  with 
than  stenosis,  particularly  in  swine. 

Etiology. — Obstruction  and  stenosis  of  the  esophagus 
are  primary  causes  of  esophageal  dilatation,  but  it  may 
be  the  result  of  traction  from  without. 

Lesions. — Dilatation  usuallj^  affects  the  entire  circum- 
ference of  the  esophagus,  although  in  some  instances  the 
dilatation  may  be  lateral  and  form  a  true  diverticulum. 
In  the  dilated  portion,  the  esophageal  walls  are  usually 


THE  DIGESTIVE  SYSTEM  19 

attenuated,  and,  in  rai'e  instances,  tlioy  may  become  so 
weak  that  they  are  easily  ruptured. 

Symptoms. — The  usual  symptoms  evidenced  in  an 
animal  afflicted  with  esophageal  dilatation  consist  of  a 
gradually  developing  tumefaction  or  enlargement  in 
the  cervical  region  while  the  animal  is  eating,  due  to  the 
accumulation  of  the  food  in  the  dilated  portion  of  the 
esophagus.  The  enlargement  gradually  subsides  after 
eating,  until  no  enlargement  is  observed. 

Treatment. — The  treatment  of  esophageal  dilatation 
is  of  little  avail,  and  is  primarily  confined  to  surgical 
interference. 

Perforation 

Esophageal  perforation  is  not  very  common  in  swine. 

Etiology. — It  may  be  the  result  of  erosion  due  to 
disease  processes,  such  as  actinomycosis,  tuberculosis,  or 
necrobacillosis,  resulting  in  a  complete  destruction  of 
portions  of  the  esophageal  walls  and  thus  permitting  the 
contents  of  the  esophagus  to  infiltrate  into  the  surround- 
ing structures. 

Perforation  may  also  result  from  injury  due  to  some 
foreign  body  that  has  been  ingested  and  lodged  in  the 
esophagus.  Weston  reported  the  case,  in  The  American 
Veterinary  Review  (Vol.  40,  p.  658),  of  a  hog  that  had 
swallowed  a  piece  of  sharp  tin,  which  had  perforated  the 
thoracic  portion  of  the  esophagus.  A  sinus  was  formed 
in  the  adjacent  lung,  in  which  a  small  mass  of  food  had 
accumulated. 

Lesions. — The  lesions  resulting  from  perforation  of 
the  esophagus  are  quite  variable  and  consist  not  only  of 
the  destruction  of  the  esophageal  walls,  but  also  of 
tissue  changes  induced  by  the  escape  of  food  from  the 
esophagus  in  the  surrounding  tissues.  In  some  instances 
the  primary  lesions  consist  of  an  inflammatory  edema, 
while  in  other  instances  the  primary  lesions  are  tuber- 
culous, actinomycotic,  or  necrobacillary . 

Symptoms. — ^The  symptoms  resulting  from  eso- 
phageal   perforation    vary    according    to    the    secondary 


20  SWINE  DISEASES 

lesions  evolved.  There  may  or  may  not  be  tumefaction 
of  the  tissues  adjacent  to  the  perforation.  In  all  cases, 
there  will  be  more  or  less  difficulty  in  deglutition,  and  in 
extreme  cases  there  will  be  aphagia. 

Treatment. — The  treatment  of  esophageal  perfora- 
tion depends  upon  removing  the  cause  and  healing  the 
injuries,  combined  with  proper  diet. 

Esophagitis 

Esophagitis  in  hogs  is  not  very  common.  It  may  be 
the  result  of  the  injury  from  foreign  bodies,  exposure,  or 
infection. 

Catarrhal  esophagitis  is  perhaps  the  most  frequent 
type  of  inflammation  and  may  be  local  or  general.  The 
usual  lesions  evidenced  in  the  acute  type  consist  of  con- 
gestion, infiltration,  and  tumefaction  of  the  nmcous 
membrane,  associated  with  desquamation  of  the  epi- 
thelium. Ulceration  may  occur.  The  chronic  type  is 
characterized  by  an  excessive  development  of  fibrous 
tissue  in  the  submucosa,  and  causes  the  mucous  mem- 
brane to  be  thrown  into  folds.  Chronic  esophagitis  is 
occasionally  observed  in  hogs  that  are  fed  exclusively 
on  distillery  slops. 

Croupous  esophagitis  is  usually  the  result  of  an  invasion 
of  Streptococci,  although  this  condition  may  be  associated 
with  hog  cholera  or  pneumonia.  The  disease  is  charac- 
terized by  the  accumulation  upon  the  mucous  membrane 
of  a  yellowish  or  brownish  coagvdated  exudate. 

Phlegmonous  esophagitis  is  usually  observed  as  a 
sequel  of  perforation,  or  the  escape  of  pus  into  the  sub- 
mucosa from  abscesses.  This  condition  is  sometimes 
associated  with  phlegmonous  pharyngitis.  The  accumu- 
lated pus  or  other  inflammatory  exudate  is  frequently 
so  extensive  that  the  lumen  of  the  esophagus  is  entirely 
closed. 

Tumors 

Tumors  of  the  esophagus  are  relatively  rare.  Polypoid 
fibromas  have  been  observed,  and  more  rarely  myxomas 


THE  DIGESTIVE  SYSTEM  21 

and  myomas.     Malignant  tumors  of  the  esophagus  are 
quite  rare,  and  wlien  they  do  occur  they  are  secondary. 

STOMACH 

Malformations 

Malformations  of  the  stomach  are  comparatively 
rare  in  hogs.  The  stomach  may  be  abnormally  small 
and  sometimes  there  is  a  constriction  in  the  middle  line 
producing  the  so-called  hour-glass  stomach. 

Foreign  Bodies 

'  Foreign  bodies  in  the  stomach  are  comparatively 
frequent  because  hogs  have  a  marked  tendency  to  swallow 
objects  of  various  kinds.  The  following  was  found  in 
one  hog's  stomach: 

40  nails.  1  No.  10  shotgun  shell. 

15  staples.  2  buggy-top  tacks. 

4  screws.  5  pieces  of  iron. 

4  nuts.  1  metal  picture  frame. 

9  pebbles.  6  pieces  of  zinc. 

1  snap.  8  pieces  of  wire. 

2  bolts.  1  piece  of  glass. 
1  brass  pin.  1  piece  of  brass. 
1  piece  porcelain. 

Hair  balls  (trichobezoars)  are  occasionally  observed 
in  swine. 

The  damage  due  to  foreign  bodies  in  the  stomach  of 
swine  depends  upon  their  nature.  Some  sharp  objects 
inflict  wounds  of  various  dimensions,  and  in  some  in- 
stances perforation  occurs,  succeeded  by  peritonitis. 

Lesions. — The  lesions  will  vary  with  the  nature  of 
the  foreign  objects;  in  some  cases  there  is  only  a  catarrhal 
condition,  while  in  other  instances  there  may  be  laceration 
or  even  perforation  of  the  stomach  walls. 

Symptoms. — Evidences  of  gastric  foreign  bodies  are 
by  no  means  sufficiently  distinct  to  differentiate  this 
condition  from  various  other  gastric  disorders. 

Treatment. — Little  is  available  in  the  form  of 
treatment  of  swine  that  have  ingested  foreign  bodies. 
Small  objects  may  be  expelled  by  vomition  excited  by 


22  SWINE  DISEASES 

emetics,  or  may  be  removed  by  gastric  lavage.  Objects 
imbedded  in  the  gastric  walls  can  be  removed  only  by 
surgical  interference,  but  gastric  surgery  in  swine  is  not 
well  developed  at  this  time. 

Vomition  (Emesis) 

Vomition  is  rather  common  in  swine  and  is  the  result 
of  stimulation  of  the  vomition  center,  which  is  located 
in  the  medulla.  This  stimulation  may  be  direct  from 
irritation  in  the  nerve  center,  but  more  frequently  it  is 
indirect  from  irritation  of  some  portion  of  the  gastro- 
intestinal tract.  Vomition  is  therefore  a  symptom  of  a 
variety  of  disease  conditions.  It  maj^  be  caused  by 
engorgement  of  the  stomach,  nature  having  provided 
this  method  of  relieving  an  overloaded  stomach.  In- 
testinal obstruction  is  another  frequent  cause  of  vomition 
in  swine,  as  is  also  irritation  of  the  mucosa  of  the  eso- 
phagus, intestine,  and  more  especially  the  stomach. 
Thus  hog  cholera  is  frequently  evidenced  by  vomition. 
Gastric  parasites  not  infrequently  cause  sufficient  irri- 
tation to  produce  violent  vomition,  particularly  in  small 
pigs,  while  chemical  irritants  acting  upon  the  digestive 
mucosa  may  produce  vomition. 

Swine  as  a  rule  vomit  easily.  The  affected  animals 
become  uneasy  and  restless.  They  extend  the  head  and 
depress  the  nose,  the  esophageal  muscles  are  relaxed, 
the  abdominal  muscles  contract,  and  the  stomach  con- 
tent is  thus  forced  out.  The  vomited  material  usually 
consists  of  particles  of  food  admixed  with  mucus,  although 
it  may  be  composed  entirely  of  a  thin,  shiny  nmcus. 
The  expelled  material  may  contain  intestinal  as  well  as 
gastric  contents. 

Anemia 

Anemia  of  the  nuicous  membrane  of  the  stomach 
occurs  in  swine  after  surgical  operations  in  which  large 
quantities  of  blood  have  been  lost.  It  may  also  be 
due  to  obstruction  of  the  arteries  suj)plying  the  gastric 
walls. 


THE  DIGESTIVE  SYSTEM  23 

A  long-continued  anemia  of  the  stomach  results  in 
atrophy  of  its  walls.  An  anemic  stomach  is  pale,  flabby, 
and  bloodless. 

Gastric  anemia  results  in  improper  digestion,  which 
ultimately  leads  to  emaciation  and  possibly  to  other 
disturbances  of  the  animal  body. 

Hemorrhage  (Hematemesis) 

Etiology — Hemorrhage  of  the  stomach,  or  hematemesis 
is  the  result  of  erosion  of  blood  vessels  due  to  diseased  pro- 
cesses, traumatisms,  and  caustics.  Hog  cholera  is  the 
most  frequent  cause  of  gastric  hemorrhages  in  hogs. 

Petechial  hemorrhage  into  the  walls  of  the  stomach 
is  associated  with  various  infective  diseases. 

Lesions. — Erosion  or  laceration  of  the  blood  vessels 
plus  an  accumulation  of  blood  in  the  stomach  or  dis- 
charged from  the  stomach,  are  associated  with  gastric 
hemorrhage.  The  hydrochloric  acid  of  the  gastric  juice, 
acting  upon  the  blood,  forms  a  clot,  and  also  changes  the 
color  of  the  blood.  As  a  rule  the  extravasation  is  con- 
verted into  masses,  which  are  of  about  the  same  size 
and  color  as  roasted  coffee  beans.  If  the  escaped  blood 
from  the  stomach  passes  on  through  the  intestine  it  will 
remain  firmly  clotted  in  coffee-bean  masses.  These 
masses  characterize  gastric  hemorrhage  and  serve  to 
distinguish  gastric  from  intestinal  hemorrhage. 

Symptoms. — Gastric  hemorrhage  is  evidenced  by  a 
pale  mucous  membrane  and  the  escape  of  non-frothy, 
black,  and  more  or  less  coagulated  masses  of  blood  from 
the  mouth. 

Peptic  Ulcers 

Peptic  ulcers  are  rarely  observed  in  swine,  but  when 
they  occur  are  usually  near  the  pyloric  end  of  the  stomach. 

Etiology. — The  cause  of  peptic  ulcer  is  by  some  thought 
due  to  thrombotic  formation:  it  may  be  due  to  the  action 
of  gastric  juice  upon  anemic  areas  of  the  stomach. 


24  SWINE  DISEASES 

Lesions. — Peptic  ulcers  are  characteristic  in  their  ap- 
pearance. They  may  involve  the  mucous  membrane  only 
or  they  may  extend  through  the  submncosa  and  involve 
the  muscular  coat  of  the  stomach,  and  even  perforate 
the  serous  membrane.  In  size  they  vary  from  that  of  the 
cross-section  of  a  lead  pencil  to  the  area  of  a  silver 
dollar.  They  appear  as  though  made  by  means  of  a 
punch,  and  if  they  involve  more  than  the  mucous  mem- 
brane they  usually  have  a  terraced  margin;  their  walls 
being  clean-cut  and  non-inflammatory. 

Symptons. — -The  evidences  of  peptic  ulcer  vary,  but 
usually  there  is  indigestion  and  occasionally  hemorrhages. 
Sometimes  it  results  in  perforation  of  the  stomach, 
followed  by  peritonitis  and  death. 

Hyperemia 

Passive  hyperemia  of  the  stomach  is  the  result  of 
obstructive  circulation  and  usually  is  evidenced  by  more 
or  less  edema  of  the  gastric  walls;  in  extreme  cases  there 
may  be  thrombotic  formation  and  focal  or  even  extensive 
necrosis. 

Active  hyperemia  of  the  stomach  is  much  more  common 
than  the  passive  form,  and  may  be  either  physiologic  or 
pathologic. 

!  Pathologic  gastric  arterial  hyperemia  is  caused  by 
irritation,  either  from  chemicals,  undue  exposure,  or 
infection,  and  represents  the  primary  stage  of  inflam- 
mation. 

Gastritis 

Gastritis  is  relatively  common  in  hogs.  It  results 
from  traumatic  injuries,  chemical  irritants  (poisons),  and 
infection. 

Catarrhal  Gastritis 

Catarrhal  gastritis  is  of  fairly  common  occurrence 
and  usually  results  from  mild  irritation.  It  is  evidenced 
by  a  hyperemia  of  the  mucosa,  which  appears  red,  slightly 
tumefied,  and  covered  with  varying  quantities  of  mucus. 


THE  DIGESTIVE  SYSTEM  25 

Symptoms. — The  symptoms  of  catarrhal  gastritis 
vary  according  to  the  intensity  of  the  disease,  vomition 
after  eating  being  one  of  the  most  common.  There  is 
usually  increased  thirst.  In  the  beginning  of  the  disease 
there  is  often  constipation,  followed  by  diarrhea  with  a 
discharge  of  a  thin,  fetid,  fecal  material.  There  is  a 
slight  rise  of  temperature  and  usually  an  unequal  dis- 
tribution of  surface  temperature,  one  part  being  warm 
while  another  is  cold.  The  tail  drops,  and  the  animals 
have  a  tendency  to-  pile  up  or  get  under  their  bedding. 
The  course  of  the  disease  is  usually  rapid  and  recovery 
almost  certain. 

Treatment. — The  treatment  consists  in  determining 
the  cause  and  then  removing  it.  It  is  advisable  to 
empty  the  stomach  by  use  of  an  emetic,  such  as  apomor- 
phin.  The  affected  animajs  should  then  be  placed  on  a 
diet  consisting  of  a  small  quantity  of  easily  digested  food. 
Further  treatment  is  rarely  needed. 

Croupous  Gastritis 

Croupous  gastritis  is  usually  the  result  of  caustics 
ingested  with  food  stuff,  such  as  lye,  which  is  occasionally 
fed  in  large  quantities  for  the  purpose  of  warding  off 
diseases  of  various  kinds. 

Lesions. — In  croupous  gastritis  an  intense  tumefac- 
tion of  the  mucosa  is  present,  the  affected  portion  con- 
taining accumulation  of  exudate  which  is  dirty  white  or 
brown  in  color,  and  when  detached  usually  leaves  a 
bleeding  surface. 

Symptoms. — The  manifestations  of  croupous  gas- 
tritis are  similar  to  those  of  catarrhal  gastritis,  but  are 
more  intense.  The  animals  evince  gastric  pain  by 
uneasiness,  restlessness,  and  frequent  vomition.  There 
is  a  rise  of  temperature  of  from  one  to  two  degrees  Fahren- 
heit. The  affected  swine  have  little  desire  to  eat,  but 
they  show  a  tendency  to  drink  frequently,  after  which 
they  evidence  more  intense  jjain  until  they  vomit.  The 
tail  hangs  straight,  and  the  animals  have  little  tendency, 
to  move. 


l>(i  SWINE  DISEASES 

This  disease  usually  runs  a  rapid  course,  as  a  rule 
terminating  within  five  to  eight  days. 

The  prognosis  should  be  guarded. 

Treatment. — The  treatment  consists  in  giving 
demulcent  drinks  after  having  removed  the  cause.  The 
content  of  the  bowels  should  be  kept  soft  by  laxatives. 
The  affected  animals  should  be  separated  from  the 
healthy  and  given  good  quarters. 

Phlegmonous  Gastritis 

Phlegmonous  gastritis  occasionally  occurs  in  bogs 
and  is  usually  the  result  of  infection  with  streptococcic 
micro  organisms. 

Lesions. — The  anatomical  changes  occurring  in 
phlegmonous  gastritis  consist  of  an  intense  tumefaction 
of  the  mucosa  due  to  accumulation  of  pus  or  other 
inflammatory  products  in  the  subtnucosa.  Patches  of 
the  mucosa  may  become  necrotic  and  desquamate.  In 
other  instances  large  sinuous  tracts  are  formed  beneath 
the  mucosa  and  in  these  pus  accumulates  in  large  quan- 
tities. The  muscular  layers  of  the  stomach  frequently 
become  infiltrated  with  pus;  the  inflammatory  process 
may  extend  to  and  involve  the  serous  coat. 

Symptoms. — The  evidences  of  phlegmonous  gas- 
tritis are  not  distinct  and  separable  from  those  of  croupous 
gastritis.  There  is  usually  intense  pain,  indicated  by  the 
constant  change  in  position  of  the  animals.  Vomition  is 
usually  frequent,  the  vomited  material  being  small  in 
quantity  and  largely  mucous  or  mucopurulent  in  char- 
acter, and  it  is  not  infrequently  mixed  with  blood.  There 
is  inappetence,  thirst,  and  a  drawn-up  appearance  of 
the  abdomen,  with  arching  of  the  back.  The  temperature 
ranges  from  104  to  107  degrees  Fahreidieit.  Constipa- 
tion is  usually  quite  marked  in  the  beginning,  but  may  be 
succeeded  by  diarrhea. 

The  course  of  this  disease  varies  from  three  to  seven 
days.  The  prognosis  should  be  guarded,  as  the  disease 
is  usually  fatal. 


THE  DIGESTIVE  SYSTEM  27 

Treatment. — The  pain  should  be  reheved  by  de- 
mulcent drinks,  gastric  lavage,  and  enemas,  combined 
with  anodynes.  The  medication  of  swine,  especially  of 
mature  animals,  is  not  an  easy  matter. 

Chronic  Gastritis 

Chronic  gastritis  is  of  rather  frequent  occurrence  in 
hogs  and  may  be  the  result  of  irritation  by  the  Arduenna 
strongylina. 

Lesions. — The  anatomical  changes  in  the  stomach 
consist  of  a  fibrous  proliferation  which  may  destroy  the 
gland  tissues  or  obstruct  their  ducts,  resulting  in  the 
formation  of  small  cysts.  The  mucosa  is  usually  attenu- 
ated, due  to  atrophy  of  the  mucous  membrane.  As  a 
rule  there  is  some  ulceration  and  not  infrequently  the 
capacity  of  the  stomach  is  diminished,  due  to  the  con- 
traction of  the  newly  formed  fibrous  tissues. 

Symptoms. — The  symptoms  of  chronic  gastritis  of 
swine  are  not  distinct.  There  is  variation  of  appetite. 
Vomition  immediately  after  eating  may  or  may  not  be 
present.  Affected  animals  are  unthrifty  as  a  result  of 
nutritive  disturbances. 

This  is  essentially  a  chronic  disease,  the  courses 
varying  from  a  few  weeks  to  months.  Prognosis  is 
favorable  as  to  the  life  of  the  animal,  but  unfavorable 
as  to  the  relief  of  the  condition. 

Treatment. — Treatment  consists  in  strictly  limiting 
the  diet  to  easily  digested  foods,  and  the  maintenance  of 
a  laxative  condition  of  the  bowels. 

Dilatation 
Dilatation  of  the  stomach  may  be  acute  or  chronic. 

Acute  Gastric  Dilatation 

Acute  dilatation  is  a  condition  resulting  from  a  rapid 
distention  of  the  stomach,  a  condition  not  very  common 
in  swine. 

Etiology. — Acute  dilatation  is  usually  due  to  over- 
loading the  stomach.     It  is  most  frequently  caused  by 


28  SWINE  DISEASES 

the  ingestion  of  large  quantities  of  indigestible  substances, 
or  of  foods  that  are  easily  and  extensively  fermentable. 

Lesions. — The  lesions  observed  in  acute  dilatation 
consist  of  enlargement,  the  walls  being  very  much  attenu- 
ated. Rupture  of  the  stomach  may  occur  in  the  greater 
curvature. 

Symptoms. — The  evidences  of  acute  dilatation  are 
the  same  as  those  of  overloading  of  the  stomach.  Rest- 
lessness, succeeded  by  vomiting,  is  the  usual  sign  observed 
in  the  early  stages  of  a  limited  dilatation.  In  some 
instances  the  walls  of  the  stomach  become  so  thin  due 
to  extreme  distension,  that  vomition  is  not  possible, 
and  such  cases  are  evidenced  by  gagging,  salivation,  and 
bloating,  if  the  distension  is  due  to  foods  that  readily 
ferment.  Extreme  distension  produces  distress  and 
expressions  of  pain. 

Diagnosis. — Diagnosis  of  gastric  dilatation  is  depend- 
ent upon  history  and  the  symptoms  indicated  above. 
Prognosis  should  be  guarded,  as  the  possibility  of  rupture 
must  always  be  considered. 

Treatment.— When  the  dilatation  is  not  too  great, 
the  treatment  should  be  largely  confined  to  removal  of 
the  gastric  content  by  emetics,  and  to  lavage  when  the 
dilatation  is  extensive  and  likely  to  result  in  rupture. 

Chronic  Gastric  Dilatation 

Chronic  gastric  dilatation  is  not  common  in  swine 
but  has  been  observed.  Accumulation  of  indigestible 
substances  is  the  usual  cause  of  the  trouble.  Occasional 
cases  have  been  observed  where  there  was  a  sufficient 
accumulation  of  hair  in  the  stomach  to  permanently 
dilate  it  beyond  the  normal  capacit3^ 

Symptoms. — The  usual  evidences  of  chronic  gastric 
dilatation  consist  of  irregular  appetite,  associated  with 
unthriftiness.  The  stomach  is  distended,  and  may  con- 
tain various  foreign  bodies  or  indigestible  substances. 
The  gastric  mucosa  is  usually  affected  with  chronic 
catarrh. 


THE  DIGESTIVE  SYSTEM  29 

Treatment. — This  condition  is  not  very  successfully 
treated  because  of  the  tendency  to  permanent  dilatation 
of  the  stomach.  Dieting,  especially  with  easily  digestible, 
concentrated  foods,  is  especially  advised. 

Tumors 

Tumors  of  the  stomach  of  swine  are  not  very  preva- 
lent, or  at  least  such  cases  are  rarely  reported. 

Fibromas  have  been  observed  in  only  a  few  instances. 
They  usually  involve  the  serous  coat  and  rarely  become 
of  sufl^cient  magnitude  to  cause  damage  other  than 
slight  mechanical  interference.  These  tumors  are  in- 
variably incapsulated,  and  appear  as  a  dense,  fibrous 
mass. 

Lipomas  occur  in  the  serous  coat  of  the  stomach  of 
swine  though  they  are  not  common.  A  few  such  tumors 
have  been  observed,  and  in  one  instance  the  tumor  had 
become  so  large  that  it  seriously  interfered  with  the 
function  of  the  organ  by  displacing  the  stomach  and 
producing  such  pressure  that  it  practically  occluded  the 
duodenum  and  resulted  in  death.  Lipomas  appear  as 
more  or  less  nodular  masses,  and  are  invariably  incapsu- 
lated. 

Of  the  malignant  tumors,  carcinoma  and  adenoma 
have  been  observed,  although  they  too  are  rather  infre- 
quent and  do  not  appear  to  be  so  injurious  to  the  health 
of  swine  as  the  same  kinds  of  tumors  are  to  horses  or 
even  to  cattle.  Carcinomas  may  develop  in  the  sub- 
mucosa  and  project  into  the  lumen  of  the  intestine 
as  a  cauliflower-like  mass,  or  they  may  develop 
in  the  mucosa,  producing  erosions  not  only  of  the 
mucous  membrane,  but  of  the  other  structures  of  the 
stomach  wall,  ultimately  causing  perforation  and  fatal 
peritonitis.     These  tumors  are  not  incapsulated. 

The  symptoms  evolved  as  a  result  of  tumors  are  quite 
variable  and  not  sufficiently  characteristic  to  permit  a 
positive  antemortem  diagnosis. 

The  treatment  of  gastric  tumors  is  entirely  surgical. 


30  SWINE  DISEASES 

Parasites 

Arduenna  strongylina  is  a  very  common  parasite  in 
the  stomach  of  swine.  In  the  central  United  States  it  is 
probable  that  at  least  ninety  per  cent  of  swine  are  infested. 
They  are  a  small,  thread-like,  white  worm,  varying  in 
length  from  three-fourths  of  an  inch  to  one  and  one-half 
inches,  usually  more  or  less  coiled,  although  they  may  be 
found  practically  straight.  They  may  be  found  in  masses 
in  the  submucosa,  free  upon  the  mucous  membrane, 
extending  into  the  gastric  glands,  or  even  perforating 
the  mucous  membrane.  They  injure  their  host  by 
direct  abstraction  of  nutriment,  by  obstruction  of  gastric 
glands,  by  destruction  of  tissue,  and  by  irritation.  The 
usual  condition  resulting  from  infestation  with  these 
parasites  is  chronic  gastric  catarrh. 

Symptoms. — Symptomatically  the  infestation  with 
large  numbers  of  the  Arduenna  strongylina  is  evidenced 
by  variation  of  appetite,  and  usually  by  constipation, 
unthriftiness,  and  rough  coat.  It  is  doubtful  if  any 
symptoms  would  be  sufficiently  prominent  upon  which 
to  base  a  diagnosis  in  cases  in  which  the  infestation  is 
limited  to  a  few  worms. 

Treatment. — Treatment  of  gastric  parasitism  is 
not  difficult  providing  the  parasites  are  free  upon  the 
surface,  but  successful  treatment  is  difficult  in  cases  where 
the  parasites  have  passed  through  the  mucous  membrane 
into  the  submucosa.  The  usual  anthelmintic  treatment 
is  most  easily  applied  in  the  food  or  slop.  Ferrous 
sulphate,  copper  sulphate,  or  oil  of  turpentine  may  be 
mixed  with  slops.  Santonin  given  with  food  is  of  value, 
but  creosote  in  the  slop  is  probably  most  efficient. 

The  Siraondsia  paradoxa  infests  the  stomach  of 
swine,  but  is  probably  not  found  in  the  United  States, 
although  quite  prevalent  in  some  sections  of  Europe. 
The  lesions,  symptoms,  and  treatment  are  similar  to 
those  given  for  Arduenna  strongylina. 

Ascaris  suum  is  found  occasionally  in  the  stomach, 
but  its  natural  habitat  is  the  intestine,  and  it  will  be  dis- 
cussed later  in  that  relation. 


THE  DIGESTIVE  SYSTEM  31 

INTESTINES 

Malformations 

Total  absence  of  the  intestine  is  rare  and  occurs 
practically  only  in  acardiac  monsters. 

Atresia  ani,  that  is,  the  failure  of  development  of  the 
anus,  is  relati^•ely  common.  This  condition  results  from 
the  failure  of  invagination  of  the  skin  surface  which 
normally  extends  to  and  fuses  with  the  rectum.  Pigs  so 
affected,  unless  the  defect  is  relieved  by  operation,  die 
the  first  or  second  day  after  being  farrowed.  The 
defect  is  as  a  rule  easily  corrected  by  operation  in  which 
crucial  incisions  are  made  through  the  skin  and  the 
terminal  end  of  the  rectum,  the  skin  and  rectal  triangular 
flaps  being  interdigitated  and  maintained  by  sutures. 

Cloacal  formation  in  which  there  is  a  common  opening 
for  the  intestine,  uterus,  and  vagina  or  ureters  sometimes 
occurs,  but  this  is  not  a  serious  defect,  except  in  breeding 
animals. 

Diverticula  are  not  rare.  They  are  usually  the  per- 
sistent remnants  of  the  vitellin  or  omphalomesenteric 
duct.  They  do  not  as  a  rule  interfere  with  the  health  of 
the  animal. 

Transposition,  particularly  of  the  large  colon,  may 
occur,  but  is  not  of  any  significance  except  as  a  pathologic 
condition. 

Congenital  hernia  may  occur.  The  outcome  depends 
upon  the  extent  and  nature  of  the  defect. 

Hemorrhage  (Enterorrhagia) 

Enterorrhagia  occurs  rather  commonly  in  swine. 

Etiology. — Mechanical  injury  of  the  structure  of  the 
intestine  by  ingested  foreign  bodies  is  a  common  cause  of 
hemorrhage.  In  extreme  cases  of  constipation  the 
accumulated  fecal  matter  may  become  so  desiccated 
that  it  readily  produces  abrasions  of  the  intestinal  mucosa, 
resulting  in  hemorrhage.  Parasites,  particularly  the 
Gigantorhynchus  hirudinaceus,  may  also  produce  hemor- 
rhage.    Intestinal  hemorrhage  is  a  common  symptom  of 


32  SWINE  DISEASES 

liog  cholera,  anthrax,  septicemia,  cryptogamic  poisoning, 
caustic  poisoning,  and  severe  inflammatory  <listiirl)ances 
of  the  intestine. 

Lesions. — The  particular  lesion  identifying  intestinal 
hemorrhage  is  the  extravasated  blood  which  may  or  may 
not  be  thoroughly  admixed  with  the  intestinal  content. 
If  the  hemorrhage  has  been  extensive  there  will  be  a 
general  anemia  of  the  entire  mucosa.  Lesions  of  the 
intestinal  mucosa  will  be  observed  in  those  cases  in  which 
the  hemorrhage  has  been  induced  by  trauma  or  chemical 
irritants.  There  may  be  no  evidence  of  intestinal 
mucous  membrane  lesions  in  the  infective  diseases  like 
hog  cholera,  as  the  hemorrhages  in  these  cases  are  usually 
the  result  of  blood-vessel  lesions  rather  than  mucosa 
lesions. 

Symptoms. — The  first  evidence  of  intestinal  hemor- 
rhage is  the  passing  of  the  blood  from  the  anus.  If  the 
discharged  blood  is  thoroughly  admixed  with  the  feces 
and  of  a  brownish  cast  it  indicates  that  the  hemorrhage 
has  been  well  forward  in  the  small  intestine.  If  the 
discharged  blood  occurs  in  masses,  not  mixed  w^tli  the 
fecal  matter,  and  has  the  normal  blood  color,  it  indicates 
that  the  hemorrhage  has  been  in  the  anteridr  portion  of 
the  large  intestine;  and  if  the  fecal  matter  is  streaked 
with  l^lood  on  the  outer  surface  only,  the  hemorrhage 
occurred  in  the  rectum.  The  visible  mucous  membranes 
will  be  pale,  pulse  rapid  and  almost  imperceptible,  and 
there  will  be  weakness  associated  with  uncertain  gait. 

Diagnosis. — The  diagnosis  of  enterorrhagia  is  usually 
not  difficult,  although  it  may  not  be  an  easy  matter  to 
determine  the  exact  cause  of  the  condition.  In  gastric 
hemorrhage  the  extravasated  blood  that  passes  through 
the  bowel  is  gramilar  and  of  a  black  color;  the  extravasate 
from  intestinal  hemorrhage  is  massive,  occurs  upon  the 
surface  of  the  feces,  and  is  normal  in  color. 

Treatment. — ^The  treatment  of  intestinal  hemorrhage 
is  problematic,  and  the  relief  from  this  condition  is 
dependent  upon  removing  the  cause,  which  is  not  always 
possible.     The   affected   animals   should   be   kept   quiet. 


THE  DIGESTIVE  SYSTE^I  33 

Ergot  may  be  used  to  advantage.     Astringents  combined 
with  laudanum  may  produce  the  desired  results. 

Obstruction 

Intestinal  obstruction  is  a  condition  resulting  from 
the  occlusion  of  the  intestine  by  foreign  bodies,  inspissated 
fecal  material,  parasites,  abscesses,  tumors,  cicatrices, 
rotation  of  the  intestine  upon  itself  or  volvulus,  and 
invagination  or  intussusception.  Intussusception  is  not 
as  common  in  the  hog  as  in  some  other  animals  because  of 
the  arrangement  of  the  mesentery,  although  it  may,  and 
sometimes  does,  occur. 

Lesions. — The  anatomical  changes  observed  in 
intestinal  obstruction  vary  according  to  the  cause  and 
duration  of  the  condition.  Thus  foreign  bodies,  such  as 
hair  balls  or  nails,  may  be  found;  a  tangled  mass  of 
Ascaris  suum  is  sometimes  the  only  lesion;  abscess,  tumor 
formation,  or  changed  relation  of  the  intestine  may  be 
the  principal  lesion.  Aside  from  the  obstructing  agent 
there  may  be  inflammatory  or  necrotic  lesions  of  the 
mucous  membrane  or  other  portions  of  the  intestine. 

Symptoms. — The  first  evidence  is  inappetence  and  a 
tucked  abdomen,  followed  by  infrequent  defecation  with 
the  passage  of  small  quantities  of  mucous-covered  feces. 
Frequent  attempts  at  defecation  without  the  voiding  of 
any  fecal  matter  may  occur.  Vomition  is  a  common 
symptom  in  the  later  stages.  In  some  cases  there  is 
fermentation  of  the  intestinal  content  with  an  excessive 
accumulation  of  gas,  producing  tympany. 

Treatment. — The  relief  of  intestinal  obstruction 
depends  upon  the  cause.  Obstruction  from  inspissated 
fecal  matter  may  be  overcome  by  the  judicious  use  of 
saline  laxatives  or  enemas.  Parasitic  obstruction  may 
be  overcome  by  the  use  of  vermifuges  given  orally  or  in 
enemas.  Relief  from  obstruction  due  to  tumors  or 
abscess  formation  may  be  temporarily  obtained  by 
purgatives,  but  permanent  relief  is  obtained  only  by 
removing  the  cause.  The  treatment  for  obstruction 
from  volvulus  or  intussusception  is  problematic  and  the 


34  SWINE  DISEASES 

outcome  by  no  means  certain.  Surgical  operation  may 
be  resorted  to  in  overcoming  these  conditions,  as  well  as 
in  foreign-body  obstruction.  If  the  accumulations  of 
gas  cause  alarming  symptoms,  the  trocar  may  be  used 
to  produce  immediate  relief,  and  further  fermentation 
may  be  checked  by  the  administration  of  antiferments, 
either  through  the  cannula  or  per  os.  As  soon  as  the 
animals  have  a  desire  to  eat  they  should  be  given  sparingly 
of  easily  digested  liquid  foods. 

Dilatation 

Intestinal  dilatation  is  not  of  common  occurrence  in 
swine. 

Etiology. — The  usual  cause  is  partial  obstruction, 
resulting  in  excessive  accumulations  of  food  which  produce 
atony  and  later  a  relaxation  and  dilatation  of  the  intestinal 
walls.  Should  the  dilatation  be  unequal,  diverticular 
dilatation  results. 

Lesions. — The  usual  lesions  observed  in  intestinal 
dilatation  consist  of  distended  intestine  with  an  accumu- 
lation of  excessive  quantities  of  food  material  in  it  and 
usually  an  associated  condition  that  produces  the  primary 
obstruction. 

Symptoms. ^ — Symptomatically,  the  dilatation  is  not 
positively  differentiated  antemortem  from  obstruction, 
the  symptoms  of  both  conditions  being  practically 
identical. 

Treatment. — In  cases  of  dilatation,  remove  that 
which  primai'ily  causes  an  obstruction  and  then  administer 
tonics  to  facilitate  the  return  of  intestinal  tonicity. 

Emphysema 

Single  air  cysts  or  clusters  of  air  cysts  are  not  of 
infrequent  occurrence,  involving  and  i)rotruding  the 
serous  coat  of  the  intestine.  This  condition  appears  to 
produce  no  inconvenience  and  is  of  no  particular  economic 
importance.  It  has  been  thought  to  be  the  result  of 
bacteria,  probably  of  the  colon  group,  which  have  pene- 
trated through   the  intestinal   wall   to  the  serous  coat. 


THE  DIGESTIVE  SYSTEM  35 

where  they  produce  fermentation  and  the  gas  evolved 
is  accumulated  beneath  the  serous  membrane.  These 
air  cysts  vary  in  size  from  a  pinhead  to  a  pea,  and  there 
may  be  only  a  limited  number  of  them  or  myriads. 
Occasionally  they  are  so  prevalent  that  the  intestine 
will  float  on  water. 

Enteritis 

Enteritis  is  inflammation  of  the  intestine  and  may 
be  catarrhal,  croupous,  diphtheritic,  mycotic;  simple  or 
infective,  acute  or  chronic. 

Catarrhal  enteritis  may  be  either  acute  or  chronic. 

Acute  Catarrhal  Enteritis 

Acute  catarrhal  enteritis  is  a  common  ailment  of 
swine. 

Etiology. — The  usual  cause  of  this  disease  is  improper 
food.  The  natural  habits  of  swine  are  conducive  to  the 
introduction  of  various  microbes  into  their  food  and 
drink,  and  swine  are  frequently  fed  on  materials  that 
are  partially  decomposed.  Their  food  not  infrequently 
contains  chemical  substances  that  are  sufficiently  irri- 
tating to  establish  a  catarrhal  gastritis  and  enteritis. 
The  ingestion  of  foods  of  extreme  temperatures  may 
excite  catarrhal  enteritis;  not  infrequently  parasites 
occur  in  sufficient  numbers  to  produce  local  irritation  of 
sufficient  extent  to  result  in  catarrhal  enteritis;  finally, 
acute  catarrhal  enteritis  may  be  associated  wnth  a  variety 
of  infective  diseases. 

Lesions. — The  lesions  may  be  localized  or  they  may 
be  general,  involving  practically  the  entire  intestinal 
mucosa.  In  the  beginning  the  affected  mucous  mem- 
brane is  red,  tumefied,  and  rather  dry,  but  later  it  becomes 
coated  with  mucous  which  is  produced  in  excessive 
quantities  as  the  disease  progresses.  The  submucosa 
may  be  swollen,  due  to  the  accumulation  of  inflammatory 
exudate.  The  tumefaction  of  the  mucosa  sometimes 
effectually  closes  the  ducts  of  the  intestinal  glands,  thus 
forming  retention  cysts,  and  the  villi  are  turgescent  and 


36  SWINE  DISEASES 

have  a  velvety  appearance.  The  lymphoid  tissue  usually 
becomes  swollen  and  contains  excessive  quantities  of 
leukocytes,  which  may  be  expressed  as  a  milky  substance. 
There  may,  in  the  advanced  stages,  be  areas  of  necrosis 
of  the  epithelium  of  the  mucous  membrane.  In  the 
submucosa,  hemorrhages  of  varying  size  may  occur. 

Symptoms. — Acute  catarrhal  enteritis  occurs  most 
frequently  in  connection  with  acute  catarrhal  gastritis, 
and  the  symptoms  of  gastritis  usuallj^  overshadow  those 
of  enteritis.  Inappetence  or  variation  of  appetite,  rise 
of  temperature,  listlessness,  and  arched  back  are  common 
symptoms  of  acute  gastrointestinal  catarrh.  The  symp- 
toms of  acute  intestinal  catarrh  are  frequent  defecation 
of  small  quantities  of  mucous-coated  feces.  In  the 
beginning,  there  is  usually  constipation,  but  this  con- 
dition is  succeeded  by  diarrhea.  The  affected  animals 
groan  and  roll  frequently. 

Treatmient. — Remove  the  cause.  Give  easily  di- 
gested foods  when  appetite  returns.  If  constipation 
prevails,  give  some  laxative,  preferably  oleaginous  in 
character.  Enemas  of  warm  saline  solutions  sometimes 
give  immediate  relief. 

Chronic  Catarrhal  Enteritis 

Chronic  intestinal  catarrh  is  usually  a  sequel  of  acute 
intestinal  catarrh. 

Etiology. — The  usual  causes  of  chronic  intestinal 
catarrh  are  the  same  as  those  causing  acute  intestinal 
catarrh,  but  are  continued  over  a  longer  period  of  time 
and  probably,  in  the  majority  of  instances,  are  not  so 
intense.  Error  of  diet  is  the  most  frequent  cause. 
Chronic  heart  or  liver  diseases  that  produce  venous 
engorgement  of  the  intestine  is  a  common  cause.  Para- 
sites, no  doubt,  are  responsible  for  an  occasional  case  of 
chronic  intestinal  catarrh. 

Lesions. — The  affected  mucous  membrane  is  usually 
of  a  uniform  or  mottled  bluish,  steel,  slate  color.  The 
mucosa  is  tumefied,  dense,  and  of  a  leathery  consistency 
due  to  the  excessive  development  of  fibrous  tissue  in  the 


THE  DIGESTIVE  SYSTEM  37 

subniucosa.  Small  retention  cysts  representing  occluded 
glands  may  be  present.  The  covering  epithelium  of 
the  mucous  membrane  is  attenuated  and  sometimes 
erosions,  or  even  ulcerations,  are  observed. 

Symptoms. — Irregular  appetite,  alternation  of  con- 
stipation and  diarrhea,  rough  coat,  emaciation,  and 
malnutrition  characterize  chronic  intestinal  catarrh. 
The  foregoing  symptoms  tend  to  persist,  as  the  disease 
may  continue  for  weeks. 

Treatment. — A  proper  diet  combined  with  good 
surroundings  are  prerequisites  for  the  successful  treat- 
ment of  cases  of  chronic  intestinal  catarrh.  Regulation 
of  the  bowels,  with  maintenance  of  the  proper  con- 
sistency of  the  fecal  matter,  is  highly  important.  Treat- 
ment must  be  persistent,  as  success  will  be  attained 
only  by  a  long-continued  course  of  treatment,  combined 
with  the  proper  diet. 

Croupous  and  Diptheritic  Enteritis 

Croupous  enteritis  probably  occurs  in  swine,  but  is 
rather  uncommon,  while  diphtheritic  enteritis  is  fairly 
common. 

Etiology — The  most  common  cause  of  diphtheritic 
enteritis  is  the  Bacillus  necrophorous,  although  some 
caustic  chemicals  may  produce  the  condition. 

Lesions. — The  lesions  of  diphtheritic  enteritis  usually 
occur  in  circumscribed  areas  or  foci,  although  these  may 
be  disseminated  over  a  large  area  of  mucous  membrane. 
In  the  beginning  the  affected  portion  is  intensely  red 
and  tumefied,  and  later  a  coagulated  exudate  occurs 
upon  the  surface.  This  exudate  is  first  of  a  dirty  white 
or  gray  color,  but  may  become  brown  or  brownish-red 
and  is  not  easily  detached.  After  the  condition  has 
persisted  for  some  time  the  affected  areas  have  a  scaly 
appearance  due  to  the  fact  that  the  exudate  becomes 
loose  and  later  desquamates. 

Symptoms. — Colicky  pains,  restlessness,  drooping 
ears  and  tail,  increased  thirst,  usually  diminished  appetite, 
rise  of   temperature,   and  constipation  alternating  with 


38  SWINE  DISEASES 

diarrhea    are    manifestations    of    diphtheritic    enteritis. 
The   affected    animals   rapidly   become   emaciated. 

Treatment. — Identify  and  remove  the  cause  of  the 
trouble.  Oleaginous  laxatives  are  indicated,  and  should 
be  followed  with  demulcents.  When  the  swine  show  an 
inclination  to  eat,  give  sparingly  of  easily  digestible 
foods. 

Toxic  Gastritis,  Gastro-Enteritis, Enteritis 

A  variety  of  conditions  have  been  grouped  imder 
this  heading,  but  this  number  fortunately  is  becoming 
less  as  more  exact  investigations  are  being  concluded. 
It  is  difficult  to  clearly  distinguish  between  toxic  gastric, 
toxic  gastro-intestinal,  and  toxic  intestinal  conditions, 
and  as  a  matter  of  common  observation  it  has  been 
found  that  substances  that  ordinarily  produce  toxic 
gastritis  have  not  spent  their  entire  force  in  the  stomach, 
and  thus  continue  their  action  in  the  intestines.  On  the 
other  hand,  few  if  any  substances  are  toxic  in  the  intestine 
that  are  not  also  toxic  in  the  stomach. 

Poisoning 
Sodium  Chlorid  {Common  Salt) 

Poisoning  with  common  salt  is  rather  common. 
Swine  may  obtain  this  salt  in  cattle  yards,  or  it  may  be 
given  them  in  garbage.  Meat  brine  is  a  frequent  source 
of  salt  poisoning  and  is  verj'  destructive,  as,  unfortunately, 
swine  appear  to  relish  it.  Brine  poisoning  is  not  only 
due  to  the  contained  salt,  but  also  to  other  ingredients. 
It  has  been  found  that  from  two  to  eight  ounces  of  salt 
produce  poisoning  in  swine,  and  in  some  instances  much 
smaller  quantities  are  fatal. 

Lesions. — Sodium  chlorid  is  an  inlense  gastro- 
intestinal irritant,  ])articul;irly  when  in  a  concentrated 
solution.  In  the  l)oginiiing  the  mucous  membrane  of  the 
stomach  will  be  intensely  congested.  This  is  followed  by 
hemorrhages  upon  the  mucous  membrane,  and  inflamma- 
tory disturbances.  If  absorption  is  retarded  the  stomach 
and  bowel  content  will  contain  large  quantities  of  blood. 


THE  DIGESTIVE  SYSTEM  39 

Tlie  mucous  membrane  of  the  bladder  will  be  engorged, 
anfl  similar  lesions  may  be  observed  in  the  meninges. 

Symptoms. — Intense  thirst,  inappetence,  restless- 
ness, and  vomit  ion  are  usually  the  first  symptoms  evi- 
denced. Later  there  will  be  watery  diarrhea,  frequent 
urination,  depressed  heart  action,  muscular  weakness, 
and  paralysis.  The  animals  may  die  within  five  or  six 
hours  after  ingesting  the  salt,  or  they  may  not  die  until 
the  second  or  third  day,  if  the  quantity  consumed  has 
been  small,  they  may  survive. 

Treatment. — Emetics  should  be  employed  if  the 
animals  are  observed  immediately  after  consuming  the 
salt.  In  cases  of  several  hours'  standing,  mucilaginous 
drinks  and  rectal  injections  should  be  given.  Oleaginous 
purgatives  may  be  of  value  as  eliminants.  Heart  stimu- 
lants should  be  provided  to  avoid  cardiac  depression.^ 

Caustic  Potash,  Caustic   Soda    [Lye;    Washing 
Powders)  ^ 

It  is  a  common  practice  to  feed  swine  wash  water, 
particularly  water  that  has  been  used  for  washing  dishes 
and  in  which  liberal  quantities  of  washing  powder  or 
lye  have  been  used.  Some  swine  breeders  and  feeders 
add  varying  quantities  of  lye  to  the  feed  to  "ward  off 
disease." 

Lesions. — Caustic  alkalies  may  produce  congestion, 
inflammation,  or  necrosis,  depending  upon  the  concen- 
tration of  the  mixture.  The  lesions  will  be  diffuse  if 
the  alkali  has  been  in  solution:  they  will  tend  to  localiza- 
tion if  the  alkali  has  been  in  the  powdered  form.  In 
the  latter  case  the  lesions  occur  where  the  alkali  granules 
have  been  dej)osited  upon  the  mucous  membrane.  The 
lesions  are  usually  more  intense  in  the  stomach  than  in 
the  intestine. 

Symptoms. — Wretching,  vomition,  restlessness,  and 
muscular  weakness  are  the  usual  symptoms  evidenced  in 
the  beginning,  followed  later  by  diarrhea,  incoordination, 

^Poisoning  by  herring  brine  produces,  in  addition  to  toxic  gastro- 
enteritis, cerebral  disturbances  very  similar  to  ptomaine  poisoning. 


40  SWINE  DISEASES 

and  paralysis.  Death  may  occur  within  a  few  hours  or 
in  two  or  three  days.  Some  of  the  affected  animals  may 
recover. 

Treatment. — In  the  early  stages  emetics  should  be 
given  until  vomition  is  produced.  Later  acidulated 
water  and  oleaginous  purgatives  will  be  of  value. 

Phosphorous 

In  some  sections  of  the  country  phosphorous  com- 
pounds  are  used  in  destroying  gophers,   squirrels,   and 
other  similar  animals,  and  not  infrequently  swine  obtain 
a   sufficient    quantity    of   the   poison    to   produce   grave  ■ 
disturbances  and  even  death. 

Lesions. — The  buccal,  pharyngeal,  gastric,  and  in- 
testinal mucosa  show  inflammation.  The  liver  and 
kidneys  are  enlarged,  due  to  fatty  degeneration  of  their 
parenchyma,  and  the  heart  also  is  usually  affected  by 
fatty  changes.  The  content  of  stomach  and  bowel  are 
phosphorescent  when  examined  in  the  dark,  and  a  dis- 
tinct phosphorous  odor  emanates  from  the  stomach  and 
bowel  when  these  organs  are  opened. 

Symptoms. — Intense  thirst,  difficult  deglutition, 
vomition,  and  colicky  pains,  associated  with  weakness 
and  incoordination,  are  produced  by  phosphorous  poison- 
ing. 

Treatment. — Emetics  and  the  administration  of 
turpentine  in  mucilaginous  substances,  when  applied 
energetically,  will  sometimes  save  the  patient. 

Xanthium    Canadense  (Cocklebur) 

Cocklebur  poisoning  prevails  more  or  less  extensively 
in  the  Missouri  Valley  during  the  early  spring  months. 
Just  as  the  two  cotyledons  push  through  the  ground  is 
the  only  time  in  the  development  of  the  cocklebur  that 
it  is  poisonous,  or  possibly  s\nne  eat  the  plant  only  during 
this  stage  of  development.  The  writer  assisted  in  an 
investigation  of  the  effect  of  young  cockleburs  when 
eaten  by  swine  at  the  Kansas  Agricultural  Experiment 
Station  in  1899.     Quantities  of  the  young   plants  w^ere 


THE  DIGESTIVE  SYSTEM  41 

gathered  and  fed  to  pigs  weighing  from  forty  to 
sixty  pounds.  The  symptoms,  although  not  univer- 
sally the  same  in  all  cases,  clearly  indicated  a 
gastro-enteritis,    which    was  verified  by  autopsy. 

Lesions. — There  is  evidence  of  a  marked  gastro- 
enteritis in  animals  dead  of  cocklebur  poisoning,  usually 
involving  the  entire  mucosa  of  the  stomach  and  the 
small  intestine  and  not  infrequently  extending  to  the 
mucous  membrane  of  the  large  intestine.  The  involved 
mucous  membrane  may  slough,  leaving  large  areas  of 
denuded  surface. 

Symptoms. — Increased  thirst,  colic  pains,  diarrhea, 
weakness,  paralysis,  and  death  succeed  one  another 
rather  rapidly  in  fatal  cases.  In  some  instances  the  life 
of  the  affected  animal  is  prolonged  for  several  days, 
during  which  time  there  is  rapid  emaciation. 

Treatment. — Treatment  is  not  satisfactory.  In  the 
early  stages  emetics  may  be  of  value,  followed  by  purga- 
tives and  mucilaginous  drinks. 

Atropa  Belladonna  {Deadly  Nightshade) 

Deadly  nightshade  poisoning  is  not  of  frequent 
occurrence,  although  it  has  been  reported  in  sections  of 
the  country  where  the  plant  grows. 

Lesions. — The  lesions  are  not  characteristic.  Animals 
that  die  within  a  few  hours  will  show  no  lesions  at  all, 
except  retention  of  the  urine  or  a  greatly  distended 
bladder;  the  blood  may  be  somewhat  darker  than  normal. 
Those  that  are  affected  for  one  or  more  days  will  show  a 
gastro-intestinal  inflammation. 

Symptoms. — The  first  symptoms  noticed  are  nausea, 
followed  by  vomition,  dryness  of  the  mouth,  more  or 
less  excitement  and  convulsions,  increased  pulse  and 
respiration,  dilated  pupils,  and  partial  blindness.  The 
duration  of  this  period  is  short  and  is  followed  by  paralysis. 
The  animals  become  weak,  and  stagger,  the  temperature 
falls,  respiration  is  slow  and  weak,  gradually  becoming 
shallower,  the  pulse  is  rapid  and  weak,  and  there  is  a 
relaxation     of     the     sphincter     muscles.     The     affected 


42  SWINE  DISEASES 

animals  soon  pass  into  a  state  of  coma  in  which  death 
takes  place,  probably  due  to  asphyxiation  and  cardiac 
failure. 

Treatment. — Treatment  consists  in  administering 
the  antidotes  of  atropin;  emetics  and  purgatives;  in 
stimulating  the  heart,  and  in  resorting  to  artificial  res- 
piration. If  there  are  periods  of  excitement,  or  con- 
vulsions, the  animal  should  be  given  sedatives.  A 
valuable  aid  in  correctly  diagnosing  deadly  nightshade 
poisoning  consists  in  taking  a  few  drops  of  urine  of  the 
dead  animal  and  dropping  it  into  the  conjunctival  sac 
of  a  normal  or  healthy  animal.  If  the  poisoning  is  due 
to  atropin,  or  deadly  nightshade,  a  dilatation  of  the 
pu})il  will  occur. 

The  carcasses  of  animals  that  have  died  of  deadly 
nightshade  poisoning  putrify  very  slowly. 

Garbage 

This  is  the  time  of  conservation,  and  although  the 
feeding  of  garbage  to  swine  is  not  in  keeping  with  present 
sanitary  requirements,  it  is  upheld  by  some  as  a  means 
of  utilizing  products  that  would  otherwise  be  wasted. 

In  the  past  rather  extensive  losses  from  garbage 
feeding  have  been  reported,  but  since  the  advent  of 
anti-hog  cholera  serum  it  has  been  found  that  many  of 
the  cases  formerly  reported  as  garbage  poisoning  were 
hog  cholera,  and  it  is  certain  that  garbage  frequently  is 
contaminated  with  the  virus  of  hog  cholera. 

Garbage  poisoning  does  not  signify  any  one  definite 
kind  of  poisoning.  From  the  various  reports  of  investi- 
gators it  is  found  that  powdered  soap,  salt,  brine,  phos- 
phorous, and  arsenic  are  the  most  common  active  causes, 
although  occasionally,  no  doubt,  ptomaines  are  a  factor. 
Because  of  the  nature  of  the  poisonous  su])sta.nce,  cooking 
the  garbage  is  of  little  value. 

Lesions.  The  lesions  of  garbage  poisoning  vary  and 
are  dependent  upon  the  specific  poisonous  j)rinciple.  In 
l)ractically  all  cases  there  is  evidence  of  gastro-enteritis, 
which    may   or    may   not   be   associated   with   hepatitis. 


THE  DIGESTIVE  SYSTEM  43 

nephritis,  or  cystitis.  In  some  instances,  for  example, 
those  cases  dying  of  strychnin  i)oisoning,  no  lesions  will  be 
found. 

Symptoms. — The  symptoms,  like  the  lesions,  are 
variable  and  depend  upon  the  nature  of  the  poison. 
There  is  usually  vomition  and  diarrhea,  associated  with 
listlessness  and  drooped  ears  and  tail,  and  as  a  rule  there 
is  marked  evidence  of  colic.  The  affected  animals  may 
die  suddenly  or  they  may  linger  for  several  days;  some  of 
them  may  recover. 

Treatment. — The  further  feeding  of  the  polluted 
garbage  should  be  prohibited.  Emetics,  enemas,  and 
purgatives  to  effectually  remove  the  offending  material 
are  indicated  in  the  beginning.  If  the  specific  poison  is 
known,  the  antidote  should  be  given.  In  the  later 
stages,  treatment  of  the  various  symptoms  as  they  arise 
is  good  practice. 

Cryptogams  (Molds,   Yeast,  Bacteria) 

No  doubt  some  forms  of  garbage  poisoning  are  due  to 
molds,  yeast,  or  bacteria  that  are  capable  of  producing 
injurious  substances  in  the  alimentary  canal  or  have  by 
their  growth  and  activity  produced  injurious  substances 
in  or  upon  the  foods  prior  to  the  time  of  their  ingestion. 
Gastro-enteritis  resulting  from  the  action  or  products  of 
the  above-mentioned  vegetable  microorganisms  is  desig- 
nated cryptogamic  poisoning  or  mycotic  gastro-enteritis. 

This  condition  is  not  so  common  in  swine  as  in  some 
other  domestic  animals,  notably  the  horse.  Glover,  of 
the  Colorado  Agricultural  Experiment  Station,  has 
reported  outbreaks  of  such  a  disease  which  were  probably 
due  to  bacterially  decom])Osed  potatoes.  Some  un- 
authentic cases  have  been  reported  of  this  condition 
arising  frt)ni  the  consumption  of  moldy  alfalfa.  Cases 
have  been  observed,  but  not  frequently,  of  swine  that  had 
been  fed  upon  moldy  corn  dying  of  mj^cotic  gastro- 
enteritis and  cerebrilis. 

Lesions. — There  is  considerable  variation  in  the 
postmortem  findings  in  s\\ine  that  have  died  of  mycotic 


44  SWINE  DISEASES  . 

gastro-enteritis.  This  is  not  extraordinary,  for  there  is 
a  variety  of  molds  that  cause  this  condition.  One 
usually  finds  extensive  inflammatibn  of  the  gastro- 
intestinal mucosa,  and  in  cases  that  have  lingered  for 
some  time,  ulcerations  are  very  common.  There  is 
frequently  meningeal  engorgement,  and  in  rare  cases 
there  may  be  cerebral  softening. 

Symptoms. — There  is  inappetence,  increased  thirst, 
rise  of  temperature,  constipation  succeeded  by  diarrhea, 
weakness,  and  rapid  emaciation. 

Treatment. — Little  can  be  done  to  relieve  this  con- 
dition. Symptomatic  treatment  is  of  some  value,  and 
should  be  applied. 

Cotton-Seed  Meal 

Fatal  results  frequently,  but  not  always,  attend  the 
feeding  for  long  periods  of  cotton-seed  meal  to  swine. 
From  experiments  thus  far  conducted  it  is  apparent  that 
cotton-seed  as  a  feed  is  more  applicable  to  ruminants 
than  to  swine.  The  feeding  for  short  periods  has  in 
many  instances  been  beneficial. 

Lesions. — ^On  autopsy,  excessive  quantities  of  a 
serous  fluid  are  found  in  the  pleural  and  peritoneal 
cavities.  The  lung  is  congested,  inflamed,  and  frequently 
edematous.  Congestion  in  all  internal  organs  may  be 
observed. 

Symptoms. — The  feces  are  firm,  although  diarrhea 
may  be  present.  Unthriftiness,  irregular  appetite  or 
inappetence,  weakness,  unsteady  gait,  blindness,  and 
dyspnea  are  common  symptoms.  The  animals  finally 
assume  the  decubital  position,  and  may  struggle  or  may 
become  comatose.  Death  occurs  in  from  a  few  hours 
to  several  days,  sometimes  occurring  almost  instan- 
taneously with  premonitory  symptoms. 

Treatment. — Green  feed  and  exercise  have  a  tendency 
to  counteract  the  injurious  effects  of  cotton-seed  meal. 
Free  access  to  wood  ashes  is  a  valuable  but  not  an  absolute 
preventive  of  cotton-seed  poisoning.  Iron  compounds 
have  also  been  used  and  proved  beneficial,  while  the  wood 


THE  DIGESTIVE  SYSTEM  45 

ashes  and  iron  salts  are  preventive  but  not  curative 
agents.  The  treatment  of  affected  animals  has  not  been 
successful. 

Scours  in' Sucklings 

In  some  sections  of  the  country  scours  in  suckling 
pigs  has  become  a  menace  to  the  swine-raising  industry. 

Etiology. — There  is  apparently  no  single  cause  that  is 
responsible  for  the  various  cases  of  scours.  Unfavorable 
surroundings,  such  as  damp,  dark,  and  dingy  hog  houses, 
predispose  to  this  condition.  In  some  instances,  mammitis 
of  the  sow  is  a  causative  factor.  Improper  foods,  such  as 
moldy  or  fermented  slops,  probably  result  in  elimination 
of  injurious  substances  in  the  mother's  milk  that  will 
create  in  the  pigs  digestive  disturbances  resulting  in 
diarrhea.  Scours  may  also  result  from  infection  with 
modified  colon  bacilli.  Bacillus  necrophorous  and,  it  has 
been  reported,  certain  coccidia  are  responsible  for  a  type 
of  diarrhea  that  is  frequently  fatal  to  suckling  pigs.  It 
is  probable  also  that  intestinal  parasites  may  be  respon- 
sible for  catarrhal  enteritis  and  an  associated  diarrhea. 
Artificial  feeding  is  likely  to  produce  digestive  derange- 
ment and  diarrhea,  and  exposure  to  extreme  temperature 
variation  must  be  considered  as  a  causative  factor  of 
pig  diarrhea.  This  condition  may  occur  in  pigs  varying 
in  age  from  two  days  to  several  weeks. 

Lesions. — There  are  no  constant  lesions  associated 
with  scours  in  pigs.  The  intestinal  content  is  usually 
quite  liquid  and  may  be  putrid.  Parasites  may  be 
observed.  Some  irritation  of  the  intestinal  mucosa  may 
obtain,  and  there  may  be  ulcerations. 

Symptoms. — ^In  pig^  diarrhea  the  evacuations  are 
pasty,  the  discharges  being  of  a  grayish  or  slate  color. 
Later  the  discharge  becomes  more  watery  and  fetid, 
and  the  pig's  tail  and  hind  parts  become  soiled.  Some 
pigs  eat  heartily,  while  in  others  the  appetite  gradually 
diminishes.  The  affected  pigs  evidence  some  abdominal 
pain.     They  emaciate  rapidly,  become  weak,  and  soon 


46  SWINE  DISEASES 

appear  dejected  and  dull,  having  an  arched  back  and  an 
indisposition  to  move. 

Treatment. ^ — If  possible,  remove  the  cause.  Give 
projjcr  diet  to  the  sow  and  have  clean,  wholesome  sur- 
roundings for  the  pigs.  Medicinal  treatment  of  the 
affected  pigs,  particularly  those  depending  entirely  upon 
their  mother's  milk,  is  difficult.  It  is  a  good  practice 
to  hasten  the  removal  of  the  irritating  substances  from 
the  bowel,  by  the  use  of  castor  oil  or  similar  purga- 
tive. If  the  diarrhea  persists  after  the  correction  of 
diet  and  the  action  of  castor  oil,  small  quantities  of 
bismuth  subnitrate  may  be  used  to  advantage.  Intes- 
tinal antiseptics,  such  as  salol  and  the  sulphocarbolates 
of  sodium,  calcium,  and  zinc,  are  exceedingly  beneficial 
where  they  can  be  administered  frecpiently. 

Parasites 

The  intestine  of  swine  is  a  common  abode  for  para- 
sites. Parasitic  infestation  is  most  prevalent  in  young 
animals,  but  because  of  the  mode  of  eating  and  the 
habits  of  swine  it  is  rather  the  exception  to  find  even 
an  old  hog  entirely  free  from  intestinal  parasites.  Their 
injury  to  the  host  depends  upon  the  kind  and  the  number 
of  parasites.     Intestinal  parasites  injure  swine  as  follows: 

1.  Abstraction  of  nutrition. 

2.  Obstruction. 

(a)  Of  the  lumen  of  the  intestine. 

(b)  Of  the  lumen  of  the  hepatic  duct. 

3.  Irritation  of  mucous  membrane  due  to  movement. 

4.  Irritation  of  mucous  membrane  due  to  lip  attach- 
ment resulting  in  inflammation,  necrosis,  and  ulceration. 

5.  Liberation  of  chemical  substances  that  produce 
nervous  irritation  or  hematolysis. 

The  following  parasites  infest  the  intestine  of  swine: 

1.  Ascaris  suum. 

2.  Esophagostoma  dentatum. 

3.  Trichocephalus  crenatus. 

4.  Trichinella  spiralis. 

5.  Gigantorhynchus  hirudinaceus. 


THE  DIGESTIVE  SYSTEM  47 

Ascaris   Suum 

Ascarids  are  found  in  practically  all  hogs.  They  are 
not  blood  suckers,  but  obtain  their  nutrition  by  direct 
absorption.  The  pregnant  female  discharges  her  ova 
in  the  intestine  and  they  pass  out  with  the  feces,  where 
they  hatch  and,  so  far  as  knowT^i,  pass  through  a  portion 
of  their  life  cycle  in  decaying  matter  on  the  earth's 
surface  and  later  gain  entrance  to  the  animal  liody  with 
the  food  or  drink. 

Lesions. — These  parasites  are  round,  and  pointed  at 
either  end;  they  are  white  or  pinkish-white  in  color  and 
vary  from  six  inches  to  twelve  inches  in  length.  Usually 
they  are  found  in  the  small  intestine,  though  they  may 
occur  in  the  large  intestine  and  even  in  the  stomach. 
They  attach  themselves  to  the  mucous  membrane  by 
means  of  papillae  or  membranous  teeth,  and  produce 
irritation  to  the  mucous  membrane  as  well  as  providing 
an  avenue  of  entrance  for  a  variety  of  bacteria  which  may 
produce  inflammatory  lesions  and  even  necrosis  and 
ulceration.  The  entire  mucous  membrane  adjacent  to 
the  parasites  is  affected  by  a  catarrhal  inflammation. 
Similar  disturbances  are  observed  in  the  mucous  mem- 
brane of  the  hepatic  duct  when  it  is  infested.  The 
worms  may  form  a  mass  that  completely  obstructs  the 
intestine,  resulting  in  an  engorgement  of  the  intestine 
anteriorly  to  the  obstruction.  Occasionally  the  intestine 
may  be  perforated  and  the  offending  ascarids  found 
protruding  into  the  peritoneal  cavity,  or  they  may 
pass  through  the  intestinal  wall  and  some  of  the  intes- 
tinal content,  and,  escaping  into  the  peritoneal  cavity, 
will  produce  a  general  peritonitis. 

Symptoms. — Infestation  with  a  limited  number  of 
ascarids  probably  does  -  not  produce  any  noticeable 
symptoms.  The  symptoms  evidenced  will  vary  and 
depend  upon  the  manner  in  which  the  parasites  are 
damaging  their  host.  If  the  hepatic  duct  is  obstructed, 
there  will  be  digestive  disturbances,  associated  with 
icterus.  If  the  bowel  is  obstructed,  there  will  be  evidence 
of    obstruction    colic.     Perforation    of    the    bowel    will 


48 


SWINE  DISEASES 


result  in  peritonitis.  The  presence  of  several  of  these 
parasites  may  be  suspected  when  there  is  catarrhal 
enteritis,  especially  when  the  swine  are  being  properly 
cared  for  and  given  a  proper  diet  of  wholesome  food. 
Usually  an  occasional  worm  will  be  passed  in  the  feces. 
Unless    infestation   is    sufficient I3'    extensive   to    produce 


rig.   2— ASCARIS    SUUM. 


visible  symptoms,  a  positive  diagnosis  may  not  be  made 
until  the  parasites  are  eliminated  or  the  ova  are  identified 
in  the  feces  by  microscopic  examination.  If  this  con- 
dition persists  for  some  time  the  affected  animals  become 
unthrifty  and  emaciated. 

Treatment. — Prevention    is    far    more    satisfactory 
than  treatment  of  infested  hogs.     The  extent  of  infesta- 


THE  DIGESTIVE  SYSTEM  49 

tion  can  be  materially  diminished  by  keeping  the  quarters 
clean.  The  droppings  should  be  gathered  and  limed, 
and  the  floors  in  the  piggery  should  be  kept  clean,  and 
limed  or  sprayed  with  some  agent  that  is  destructive  to 
the  egg  and  embryo  of  the  ascarids.  Common  salt 
destroys  the  embryo  and  larvai  of  practically  all  animal 
parasites,  but  it  must  be  used  with  caution  in  hog  premises, 
for  it  is  also  quite  destructive  to  hogs. 

Treatment  of  individual  hogs  by  giving  direct  medi- 
caments is  difficult.  The  most  effectual  method  of 
medicating  swine,  particularly  when  large  numbers  are 
to  be  treated,  is  accomplished  by  medicating  the  slops 
or  feed.  Santonin  and  areca  nut  have  been  used,  but 
other  less  expensive  and  as  effectual  drugs  may  be  selected, 
such  as  ferrous  sulphate,  copper  sulphate,  and  creosote. 
When  drugs  are  mixed  with  slops  or  feed,  care  must  be 
used  to  have  a  thorough  mixture,  and  each  hog  should 
obtain  its  proper  portion.  The  medication  in  slop  or 
food  should  be  given  once  a  day  and  continued  for  several 
days.  The  excrements  laden  with  the  worms  and  their 
ova  should  be  properly  disposed  of  in  order  that  future 
infestation  may  be  diminished.^ 

Esophagostoma  Dentatum 

Esophagostomiasis  is  a  disease  caused  by  the  invasion 
of  the  Esophagostoma  dentatum  into  the  submucosa 
of  the  large  intestine  of  swine,  a  condition  not  very 
common  in  America.  This  parasite  is  parasitic  in  its 
larval  stage.  Its  life  cycle  has  not  been  entirely  worked 
out,  but  the  ova  are  discharged  from  the  animal  body 
in  the  feces  and  hatch,  if  climatic  conditions  are  favorable, 
into  embryos.  Later  changes  are  unknown,  but  the 
larvae  are  ingested  with  food  or  drink  and  bore  into  the 
submucosa  of  the  large  intestine,  where  they  remain 
from  six  to  seven   months   and  produce   small   nodules 

^The  external  covering  of  the  ascarids  contains  a  volatile  chemical 
substance  that  is  extremely  irritating  to  the  ocular  mucous  membrane, 
and  care  should  be  exercised  that  the  hands  be  carefully  cleansed  after 
handling  these  worms  and  thus  prevent  the  development  of  conjunc- 
tivitis. 


50  SWINE  DISEASES 

in  which  they  undergo  various  metamorphoses,  finally 
becoming  sexually  mature.  They  then  leave  the  sub- 
mucosa  nodules  and  migrate  into  the  lumen  of  the 
intestine,  where  copulation  occurs  and  the  female  later 
ovulates  in  the  same  location. 

Lesions. — The  principal  lesion  is  the  submucous 
nodules  that  occur  in  the  large  intestine.  There  may 
be  only  a  few  nodules,  or  there  may  be  many.  These 
nodules  are  inflammatory,  caused  by  the  presence  of 
the  larva?.  They  are  definitely  circumscribed  with  a 
fibrous  capsule;  the  content  of  which  is  inflammatory 
exudate  that  later  becomes  purulent,  then  caseous,  and 
may  ultimately  calcify.  The  nodules  first  cause  a  slight 
hard,  spherical  elevation  of  the  mucous  membrane  about 
the  size  of  millet  seed,  but  they  may  later  become  as 
large  as  a  pea.  In  the  later  stages  they  assume  a  greenish- 
gray  cast  due  to  the  accumulation  in  them  of  pus.  The 
nodules  frequently  produce  erosions  and  ulceration  of 
the  intestinal  mucosa,  and  they  may  persist  and  appear 
as  caseated  incapsulated  masses.  The  adult  parasites 
may  be  found  free  in  the  large  intestine.  They  are 
about  three-fourths  of  an  inch  in  length. 

Symptoms. — The  extent  of  invasion  sufficient  to 
produce  visible  symptoms  has  not  been  determined, 
but  it  is  not  uncommon  to  find  a  few  nodules  in  the 
intestine  of  swine  that  were  slaughtered  in  jiacking 
houses  and  were  known  to  have  been  previously  healthy. 
The  usual  symi)toms  consist  of  a  profuse  and  persistent 
diarrhea,  emaciation,  weakness,  and  death  in  the  intensely 
infested  animals.  The  disease  is  essentially  chronic. 
The  course  is  from  two  to  three  montlis. 

Treatment. ^Because  of  the  location  of  the  ofl'ending 
larvae,  medication  is  of  no  a\'ail.  A  small  percentage 
of  the  animals  may  be  saved  by  dieting  and  treating 
the  symptoms  as  they  arise.  Prevention  of  further 
spread  of  the  disease  should  be  the  chief  consideration. 

Trichocephalus   Crenatus 

This  parasite  is  not  of  connnon  occurrence  in  America. 
The   worms   are   in   shape   similar   to   the   old-fashioned 


THE  DIGESTIVE  SYSTEM  51 

blacksuake  whip,  the  head  end  very  thin  and  liair-like, 
the  i)osterior  extremity  being  thicker  and  thread-like. 
They  are  usually  coiled,  and  are  from  one  to  one  and  one- 
quarter  inches  in  length.  Their  life  cycle  is  similar  to 
that  of  the  Esoi)hagostoma.  Inl'estation  is  accomplished 
through  the  food  or  drink. 

Lesions. ^ — The  Trichocephali  are  blood  suckers,  but 
they  appear  to  do  very  little  damage  unless  they  occur 
in  large  numbers.  'When  they  jjroduce  anemia  there  is 
also  more  or  less  intestinal  catarrh.  The  parasites  are 
found  firmly  attached  to  the  nuicous  membrane  of  the 
large  intestine. 

Symptoms. — The  principal  symptoms  are  diarrhea, 
emaciation,  and  weakness. 

Treatment. — Practically  the  same  as  described  for 
the  Ascaris  suum. 

Trichinella  Spiralis 

Trichinella  spiralis  jjasses  only  the  adult  stage  of  its 
life  cycle  in  the  intestine.  The  larvsB  are  important 
muscle  parasites.  Further  discussion  will  be  found 
under  "Muscular  Parasites,"  on  page  142. 

Gigantorhynchus   Hirudinaceus 

This,  the  thorn-headed  intestinal  worm  of  swine,  is 
quite  prevalent  in  practically  all  sections  of  this  country. 
It  is  a  thick,  cylindrical,  white  worm  with  an  attenuated 
tail  portion,  transverse  markings,  and  a  head  provided 
with  a  globular  proboscis  having  several  rows  of  hooks. 
The  ova  pass  to  the  ground  with  the  feces  and  are  ingested 
by  the  larva  of  the  May  beetle,  in  which  it  passes  a 
portion  of  its  life  cycle,  the  embryo  and  larval  stages. 
Hogs  consume  the  May-beetle  larva  and  the  inclosed 
gigantorhynchus  larva  is  liberated  and  passes  into  and 
attaches  to  the  intestine  of  the  hog.  It  is  thought  that 
the  ova  may  develop  elsewhere  as  well  as  in  the  May- 
beetle  larva. 

Lesions. — Upon  opening  the  abdomen  of  a  swine 
infested  with   the   Gigantorhynchus,   shiny  nodules  of  a 


52 


SWINE  DISEASES 


grayisli  color  are  readily  visible  on  the  serous  coat  of  the 
intestine.  The  thorn  of  the  worm  is  found  to  have 
penetrated  the  mucosa,  and  Ihus  permits  of  infection 
which  results  in  the  production  of  an  inflammatory  zone. 
The  parasites  may  become  detached,  the  lesions  pro- 
duced   having    healed    by    the    formation^of    cicatricial 


Fis.    3.— GKJANTOKHVNCHl.S    HIRUDINACEUS. 


tissue,  which  is  usually  easily  recognized.  Not  infre- 
quently the  head  of  the  parasite  bores  through  the 
entire  intestinal  wall  and  occasions  general  peritonitis. 
Symptoms. — The  usual  symptoms  consist  of  di- 
gestive disturbance  the  magnitude  of  which  will  depend 
upon  the  extent  of  infestation.  The  infested  animal 
usually  gives  evidence  of  pain,  as  the  parasite  lacerates 


THE  DIGESTIVE  SYSTEM  53 

the  tissues  during  its  attachment.     There  may  also  be 
muscular  twitching. 

Treatment. — These  parasites  are  difficult  to  dis- 
lodge. Long-continued  medication  with  creosote  alter- 
nated with  copper  sulphate  has  proved  effectual  in  many 
cases. 

Tumors 

Intestinal  tumors  are  not  prevalent  and  are  of  little 
economic  importance. 

Connective  tissue  tumors  may  develop  and  mechani- 
cally interfere  with  intestinal  movement  or  they  may 
obstruct  the  lumen  of  the  bowel.  Fibromas  and  myxomas 
have  been  observed,  usually  having  their  origin  in  the 
subserosa  or  within  the  serous  coat  of  the  intestine. 
These  tumors  are  definitely  encapsulated.  It  is  usually 
not  possible  to  make  a  diagnosis  except  by  autopsy. 

Of  the  malignant  tumors,  carcinoma,  epithelioma, 
adenoma,  and  different  varieties  of  sarcoma  have  been 
identified.  The  embryonic  epithelial  tumors  may  be 
primary  or  secondary.  Primary  epithelial  tumors  usually 
have  their  origin  in  or  from  the  mucous  membrane. 
Secondary  epithelial  tumors  may  involve  any  portion 
of  the  intestinal  wall  and  are  more  frequently  encapsu- 
lated than  the  primary  tumors.  The  primary  epithelial 
tumors,  especially  epitheliomas,  are  very  prone  to  pro- 
duce necrosis  of  the  surface  mucous  membrane  and  thus 
cause  ulceration. 

General  sarcomatosis  of  the  entire  abdominal  viscera 
is  occasionally  observed.  Sarcomas  in  swine  are  appar- 
ently not  so  malignant  as  in  other  domesticated  animals, 
and  are  more  frequently  encapsulated.  The  appearance 
of  the  various  malignant  tumors  in  swine  is  the  same  or 
very  similar  to  that  of  the  same  type  of  tumor  in  other 
animals. 

Intestinal  malignant  tumors,  generally  s])eaking,  are 
evidenced  by  unthriftiness,  indigestion,  emaciation,  ma- 
rasmus, and  finally  by  death. 


54  SWINE  DISEASES 

LIVER 

The  liver  is  a  very  important  organ  physiologically, 
niui  it  is  of  such  magnitude  that  derangement  of  its 
function  and  disease  usually  result  in  marked  metabolic 
disturbance  of  the  affected  animal.  The  diseases  of 
the  liver  of  swine  have  not  received  the  attention  pro- 
portional with  other  diseases;  in  fact,  little  is  known  of 
the  pathologic  conditions  in  the  liver  of  swine  excepting 
those  observed  and  recorded  by  men  employed  in  the 
inspection  of  meat. 

Malformations 

Malformations  of  the  liver  are  not  of  much  importance. 
There  may  be  too  few  or  too  many  lobes.  The  lo})es 
may  be  entirely  separated.  Rarely,  the  gall  bladder  is 
wanting.  • 

Foreign  Bodies 

Several  hog  livers  have  been  oliserved  that  contained 
quantities  of  sand  or  cinders,  varying  in  volume  from 
an  ounce  to  a  quart.  These  cases  have  been  observed 
in  swine  killed  at  abattoirs,  and  without  exception  the 
affected  animals  were  in  prime  condition. 

The  avenue  of  entrance  of  the  sand  and  cinders  is 
no  dou})t  through  the  hepatic  duct.  Just  how  the 
foreign  substances  gain  entrance  and  "back-tell"  in  the 
ducts  to  the  gall  bladder  and  from  there  into  the  col- 
lecting cystic  ducts  in  the  liver  has  not  been  determined. 
The  hepatic  duct  orifice  in  the  summit  of  the  duodenal 
papilla  probably  becomes  enlarged  through  injury,  or 
atrophy  of  the  surrounding  mucosa,  and  this,  in  con- 
junction with  a  full  stomach  and  intestine,  would  facili- 
tate the  passage  of  the  foreign  sul)stance  through  the 
orifice  and  into  the  hei)ali('  duct.  'I'he  irritation  of  the 
foreign  su})stance  may  cause  relaxation  of  the  sphincter 
muscles  and  also  establish  reverse  peristalsis.  It  may 
be  possible  that  the  cause  may  be  due  to  irregular  action 
of  the  intestinal  musculature.  In  all  of  the  cases  observed 
the   hepatic    duct    was   found   gorged   with    the    foreign 


THE  DIGESTIVE  SYSTEM  55 

material,  the  duct  in  some  instances  being  more  than 
one  inch  in  diameter;  the  cystic  duct  and  gall  bladder 
were  found  to  contain  varying  quantities  of  the  same 
material.  In  one  case  the  gall  bladder  was  so  engorged 
with  sand  that  it  had  dilated  until  it  was  fully  as  large 
as  a  quart  measure.  The  foreign  substance,  either 
cinders  or  sand,  may  also  be  found  in  the  ducts  that 
convey  the  bile  to  the  gall  bladder.  In  some  instances 
the  biliary  capillaries  contained  considerable  quantities 
of  sand.  The  accumulations  obstructing  the  outflow  of 
bile  result  in  icterus  of  varying  intensity.  There  is 
also  a  catarrhal  inflammation  of  the  adjacent  intestinal 
mucosa  and  the  mucous  membrane  of  the  bile  tubules, 
gall-bladder,  and  hepatic  duct. 

Rupture 

Rupture  or  laceration  of  the  liver  does  occur,  although 
it  is  not  so  common  in  swine  as  in  most  other  animals 
because  the  abdominal  wall  of  swine  is  comparatively 
thick,  due  to  the  deposition  of  subcutaneous  fat. 

Etiology. — The  usual  cause  of  hepatic  rupture  is 
mechanical  interference  in  the  form  of  a  sudden  blow, 
such  as  the  kick  of  a  mule  or  the  penetration  of  the 
liver  with  some  sharp  object  which  may  lacerate  the 
hepatic  tissue. 

Lesions. — If  the  hepatic  lesion  has  caused  sudden 
death  the  peritoneal  cavity  will  contain  a  large  quantity 
of  blood  which  may  or  ma^'  not  be  coagulated,  depending 
upon  the  length  of  time  after  death  that  the  autopsy 
is  conducted.  If  the  injury  is  an  old  lesion,  cicatricial 
tissue  will  have  sealed  the  wound  and  perhaps,  by  con- 
traction, distorted  the  liver. 

Symptoms. — The  symptoms  evidenced  will  be  sliock, 
weakness,  and  blanched  visible  mucous  meml)ranes  due 
to  loss  of  blood  from  the  blood  vascular  system.  Should 
the  animal  survive  the  immediate  affect  of  the  injury 
and  the  loss  of  blood,  there  may  be  symptoms  only  of 
impaired  hepatic  function,  or  there  may  be  no  visible 
symptoms. 


56  SWINE  DISEASES 

Treatment. — Because  of  the  nature  of  hepatic 
rupture,  treatment  is  of  no  avail.  In  cases  that  will 
probably  have  a  fatal  termination  the  animal  may  be 
bled  to  death  and  the  carcass  thus  saved  for  meat. 

Icterus 

Icterus  or  jaundice  is  a  condition  resulting  from  the 
deposition  of  bile  or  bile  j)igments  in  the  various  tissues. 
This  condition  is  relatively  common  and  is  significant  as 
a  diagnostic  factor. 

Etiology. — Icterus  may  be  the  result  of  obstructed 
outflow  of  bile.  It  may  result  from  excessive  destruction 
of  red  blood  cells,  of  failure  of  elimination  of  bile  from 
the  blood.  Obstructed  outflow  of  bile  may  be  due  to 
calculi,  parasites,  or  foreign  bodies  in  the  bile  ducts, 
closure  of  the  duct  by  cicatrices,  muscular  spasms, 
tumors,  abscess,  aneurysms,  fecal  matter,  parasitic 
cysts,  or  inflammatory  disturbances  of  the  mucous 
membrane  of  the  duodenum  or  the  various  bile  ducts. 
Excessive  production  of  bile  in  the  blood  occurs  as  a 
result  of  hemolysis  due  to  chemic  substances  in  such 
diseases  as  hog  cholera,  swine  plague,  septicemia,  pyemia, 
generalized  anthrax,  phosphorous  poisoning,  and  also 
as  a  result  of  the  injection  of  the  venom  of  some 
poisonous  snakes.  Failure  of  elimination  of  bile  occurs 
not  only  when  the  outlets  are  obstructed  but  also  when 
considerable  numbers  of  liver  cells  have  been  destroyed 
or  their  functional  capacity  diminished. 

Lesions. — Bile  staining  is  most  evident  in  the  con- 
junctiva and  ocular  sclera  of  the  living  animal,  where 
it  produces  a  lemon-yellow  or  greenish-yellow  discolora- 
tion. If  the  reabsorption  of  bile  is  very  extensive  it 
may  appear  in  the  urine.  In  carcasses  biliary  pig- 
mentation is  most  evident  in  the  adipose  tissue,  especially 
the  subcutaneous  fat,  although  it  is  usually  well  marked 
in  the  subserous  fat  and  may  be  detected  in  the  lymph 
nodes,  spleen,  kidney,  and  muscular  tissues.  On  micro- 
scopic examination  the  bile  pigments  may  be  found  in 


THE  DIGESTIVE  SYSTEM  57 

the  cells  or  between  the  cells  as  greenish-yellow  amorphous 
granules. 

Symptoms. — The  effects  of  icterus  are  variable. 
The  tissues  are  discolored;  there  may  be  pruritis,  cardiac 
depression,  vomition,  coma,  and  death.  The  symptoms 
above  outlined  are  probably  not  due  to  the  presence  of 
the  bile  pigments  in  the  tissue,  but  to  other  substances 
that  have  not  been  eliminated. 

Treatment. — Removal  of  the  cause  is  usuallj^  all 
that  is  required  for  complete  recovery  from  icterus.  If 
the  cause  cannot  be  identified,  then  the  symptoms  should 
be  treated  as  they  arise. 

Cloudy  Swelling 

Cloudy  swelling,  or  parenchymatous  degeneration,  is 
a  condition  in  which  a  portion  of  the  cell  protoplasm  is 
coagulated.  This  condition  is  very  common.  It  is 
frequently  the  forerunner  of  fatty  changes. 

Etiology. — Coagulation  of  portions  of  the  cell  proto- 
plasm may  be  caused  by  high  temperature,  as  is  evidenced 
in  fever  or  overheat,  or  it  may  be  caused  by  bacterial 
products  and  other  chemical  poisons. 

Lesions. — The  affected  liver  is  enlarged,  paler  in 
color,  and  more  friable  than  normal. 

Symptoms. — The  symptoms  are  usually  associated 
with  those  of  other  disturbances  and  are  therefore  not 
specific.  There  is  evidence  of  disturbed  hepatic  function, 
and  often  a  slight  icterus  and  tendency  to  constipation. 

Treatment. — To  ascertain  and  then  remove  the 
cause  is  of  prime  importance.  This  condition  is  corrected 
only  through  the  efforts  of  the  body,  therefore,  provide 
the  proper  diet  and  maintain  sanitary  conditions. 

Fatty    Changes 

Fatty  changes  in  the  liver  are  of  common  occurrence 
in  swine.  The  usual  change  is  first  an  accumulation  of 
fat  droplets  between  the  cells  and  later  a  fatty  degenera- 
tion of  the  cells. 


58  SWINE  DISEASES 

Etiology. — Fatty  changes  in  the  Uver  may  be  due  to 
excessive  nutrition,  diminished  exercise,  hereditary  in- 
fluences, long-continued  fever,  bacterial  products,  and 
such  chemical  poisons  as  phosphorous.  Fatty  degen- 
eration of  hepatic  tissue  is  sometimes  observed  in  con- 
ditions associated  with  malnutrition. 

Lesions. — The  liver  is  enlarged,  gray  or  grayish-red 
in  color  and  lighter  than  normal  in  weight;  when  incised, 
droplets  of  fat  or  oil  may  be  observed  on  the  knife. 
Fatty  changes  are  usually  uniformly  distributed  in  the 
entire  liver;  hoAvever,  in  exceptional  cases,  one  lobe 
only  may  be  involved. 

Symptoms. — The  evidence  of  fatty  changes  in  the 
liver  are  not  characteristic.  The  condition  may  be 
suspected  in  obese  animals  or  those  known  to  be  affected 
with  chronic  arsenic,  antimony,  or  phosphorous  poisoning. 

Treatment. — There  is  no  treatment  that  is  of  any 
special  value  more  than  to  correct  the  diet. 

Amyloid  Changes 

Amyloid  changes  in  the  liver  are  rather  uncommon 
in  swine.  The  cause  is  unknown.  The  affected  liver  is 
larger,  paler,  and  firmer  than  normal.  The  amyloid 
areas  are  homogenous  and  translucent  in  appearance, 
the  amylaceous  substances  usually  occurring  in  definite 
foci,  though  they  may  be  quite  diffuse.  This  condition 
may  be  associated  with  other  diseases  which  tend  to 
mask  any  specific  symptoms.  One  case  of  amyloid 
change  has  been  observed  in  a  hog  that  clinically  showed 
no  manifestation  of  disease  and  was  in  prime  condition 
at  the  time  of  slaughter.  The  amylaceous  substance  is 
insoluble,  and  the  condition  is  therefore  probably  incur- 
able. 

Glycogenic  Infiltration 

Glycogenic  infiltration  is  a  condition  in  which  excessive 
quantities  of  glycogen  accumulate  in  the  liver.  This 
condition  is  observed  occasionally  in  the  liver  of  slaugh- 
tered swine. 


THE  DIGESTIVE  SYSTEM  59 

Etiology. ^ — Disturbed  carbohydrate  metabolism  is 
inseparably  associated  with  glycogenic  infiltration,  al- 
though the  specific  relation  of  disturbed  carbohydrate 
metabolism  and  glycogenic  infiltration  is  not  known. 
Inflammatory  disturbances  and  tumor  formation  appear 
to  have  some  relationship  with  glycogenic  infiltration. 

Lesions. — A  glycogenic  infiltrated  liver  is  pale, 
larger  than  normal,  and  of  a  putty  consistency. 

Symptoms. — No  definite  symptoms  are  attributed 
to  the  excessive  accumulation  of  glycogen  in  the  liver. 
The  condition  may  be  suspected  when  the  animals  are 
sluggish  and  do  not  exercise,  as  it  has  been  demonstrated 
that  during  muscular  activity  glycogen  is  used  in  con- 
siderable c^uantities  and  is  drawn  from  the  storehouse, 
which  is  the  liver,  as  it  is  required. 

Treatment. — Regulation  of  diet  and  exercise  is 
far  more  valuable  than  medicinal  treatment. 

Gall-stones  (Cholelithiasis) 

Gall-stones  are  accumulations  of  organic  or  inorganic 
substances  in  the  various  bile  tubes  or  gall  bladder. 
They  are  relatively  common  in  swine. 

Etiology. — The  presence  of  a  substance  that  will 
act  as  a  nucleus  is  the  first  step  in  the  formation  of  a 
calculus.  Precipitation  of  some  of  the  bile  ingredients 
is  the  second  step  in  calculus  formation,  and  the  accumu- 
lation of  the  precipitate  upon  the  nucleus  completes 
the  process.  Bits  of  mucous  or  any  particle  of  foreign 
matter  may  serve  as  a  nucleus.  Precipitation  may  be 
caused  by  supersaturation  of  the  bile  with  inorganic 
salts,  or  it  may  be  a  sequel  of  fermentation  of  bile.  In 
addition,  bacteria  and  other  factors  may  be  causative 
agents  of  calculus  formation. 

Lesions. — Cholelithiasis,  or  gall-stones,  is  found 
most  frequently  in  the  gall  bladder.  It  may  occur, 
however,  in  the  hei)atic  duct  or  in  any  of  the  collecting 
bile  tubes,  regardless  of  their  size.  The  presence  of 
gall-stones  usually  causes  obstruction  and  distention  of 
the  gall  bladder  of  the  bile  tubes  in  which  they  occur. 


60  SWINE  DISEASES 

If  the  obstruction  has  existed  for  some  time,  icterus  will 
usually  be  more  or  less  pronounced. 

Upon  opening  the  gall  bladder  or  bile  ducts  containing 
the  calculi,  thick  grumose  bile  escapes  and  the  con- 
crements  or  calculi  are  observed.  Gall-stones  may 
occur  singly,  but  they  are  usually  multiple.  They  are 
usually  of  a  brownish-chocolate  color  and  vary  in  size 
from  mere  specks  to  masses  an  inch  or  more  in  diameter. 
They  may  be  round  or  any  other  shape,  and  when  many 
are  present  they  are  usually  faceted  where  they  come 
into  contact  with  each  other.  The  gall-stones  may  be 
composed  of  organic  material  entirely  and  be  quite  soft 
or  they  may  be  incrusted  with  mineral  matter  and  be 
quite  hard.  Upon  sectioning  them  they  are  usually 
found  to  have  been  made  up  in  layers,  and  it  is  not 
difficult  to  distinguish  the  nucleus.  There  is  an  inflam- 
mation of  the  mucous  membrane  of  the  gall  bladder  or 
affected  bile  tubes. 

Symptoms. — Very  few  if  any  cases  of  cholelithiasis 
have  been  recognized  '  clinically.  If  the  gall-stones 
obstruct  the  outflow  of  bile  sufficiently  there  will  be 
general  icterus.  There  are  probably  some  digestive 
disturbances  also. 

Treatmient. — The  nature  of  this  condition  does  not 
warrant  treatment. 

Hyperemia 

Hyperemia  of  the  liver  may  be  })hysiologic  or  patho- 
logic. Physiologic  hepatic  hyperemia  occurs  after  eating 
and  is  of  no  significance  economically  or  pathologically. 
Pathologic  hepatic  hyperemia  may  be  either  venous 
(passive)  or  arterial  (active). 

Passive  hepatic  hyperemia  is  caused  by  obstructed 
outflow  of  blood.  Cardiac  defects  of  the  valves  of  the 
right  side  of  the  heart  are  a  potent  cause.  Obstruction 
of  the  posterior  vena  cava  or  the  hepatic  vein  by  new 
growths,  abscesses,  and  cicatricial  tissue  will  also  produce 
venous  engorgement  of  the  liver. 


THE  DIGESTIVE  SYSTEM  61 

Lesions. — A  caivi'ul  exaniinatioii  will  disclose  the 
lesion  producing  the  engorgement  as  well  as  the  engorged 
condition  of  the  liver.  The  liver  will  he  full  of  blood 
and  of  a  slightly  darker  color  than  normal.  If  the  con- 
dition becomes  chronic  there  will  be  fibrous  proliferation. 

Symptoms. — The  signs  of  venous  hepatic  hyperemia 
vary  according  to  the  intensity  of  the  condition  and 
its  duration.  The  animals  become  dull,  and  there  is  only 
a  sluggish  action  of  the  bowels.  If  the  condition  pro- 
gresses until  there  is  fibrous  proliferation,  disturbances  of 
nutrition  become  evident. 

Arterial  hepatic  hyperemia  may  be  the  residt  of  involve- 
ment of  the  hepatic  artery  or  of  the  portal  vein.  This 
is  a  condition  characterized  by  an  increased  inflow  of 
blood  into  the  liver.  Hyperemia  of  the  hepatic  artery 
is  not  common,  and  when  it  does  occur  it  is  usually 
chronic.  This  condition  is  usually  the  result  of  partial 
occlusion  of  the  gastric  or  splenic  branches  of  the  celiac 
axis,  although  it  may  be  caused  by  some  irritation  in 
the  terminal  vessels  in  the  hepatic  interstitial  tissue. 
No  definite  symptoms  are  evidenced,  and  the  value  of 
treatment  is  doubtful. 

Portal  hepatic  hyperemia  is  usually  caused  by  tainted 
foods  or  by  infection.  The  liver  may  be  increased  fifty 
per  cent  in  volume,  and  becomes  gorged  with  blood. 
The  symptoms  are  obscure.  Some  relief  may  be  obtained 
by  the  free  use  of  laxatives. 

Treatment. — The  removal  of  the  cause,  if  that  be 
possible,  is  about  all  that  can  be  accomplished. 

Hepatitis 

Inflammation  of  the  liver,  or  hepatitis,  is  rather 
common  in  swine.  The  condition  may  assume  either  an 
acute  or  chronic  form.  Hepatitis  as  a  rule  is  secondary  to 
other  disturbances,  although  it  may  occasionally  be 
primary.  The  inflammatory  process  may  affect  the 
liver  cells  and  is  then  designated  parenchymatous  hepatitis, 
or  it  may  affect  the  supporting  framework,  when  it 
is  designated  interstitial  hepatitis.     With  but  few  excep- 


62  SWINE  DISEASES 

tions  liej)a.titis  of  swine  hcas  not  been  made  ;i  sul>ject  of 
special  investigation"'. 

Acute  Parenchymatous  Hepatitis 

Aonte  ])arencliyma.tous  liei)atilis  is  a.  destructive 
inflainination  involving  the  liver  cells. 

Etiology. — Chemic  poisons  derived  from  the  bowel 
and  carried  to  the  liver  by  way  of  the  portal  vein  is  a 
frequent  cause  of  this  condition.  Bacterial  infection, 
entering  the  liver  by  way  of  the  portal  \-ein,  hepatic 
artery,  hepatic  vein,  umbilical  vein,  or  hepatic  duct  is 
a  common  cause  of  hepatitis.  The  Distoma  or  liver 
flukes,  the  larval  form  of  Stephanurus  dentatum,  and 
other  j)arasites  produce  hepatitis. 

Lesions. — The  liver  becomes  enlarged  and  loses  its 
sharp  outlines;  it  is  darker  in  color,  gorged  with  blood, 
and  is  more  friable  than  the  normal  liver.  There  may 
be  small  hemorrhagic  areas. 

Symptoms. — Icterus  is  usually  the  first  and  fre- 
quently the  only  evidence  of  the  disease.  The  affected 
swine  may  show  symptoms  of  ])ain  when  defecating  or 
when  moving  about. 

Treatment. — Laxatives  may  ])roduce  some  relief. 
The  proper  diet  should  be  given  and  the  animals  made 
comfortable. 

Suppurative  Hepatitis 

Suppurative  hepatitis  as  a  primary  condition  is  not 
very  common  in  swine. 

Etiology. — This  condition  is,  as  a  rule,  the  result  of 
bacterial  infection,  although  parasites  of  various  kinds 
may  ]jroduce  it.  The  infection  in  the  liver  is  usually 
secondary  and  metastatic.  Pyogenic  Staphylococci  and 
Streptococci    are    the    most    common    infecting    agents, 

•*An  enzootic  hepatitis  of  young  pigs  occurred  in  Russia  and  was 
investigated  by  Scmmer.  This  disease  has  also  occurred  in  eastern 
Prussia,  wliere  it  has  been  very  fatal.  The  cause  of  this  condition  is 
probably  a  coccus  which  is  thought  4o  gain  ("utrance  into  the  innbilicus 
at  the  time  of  farrowing.  The  affected  liver  is  enlarged,  nodular  and 
variegated  in  color. 


THE  DIGESTIVE  SYSTEM  63 

although  the  colon  bacilli  and  its  various  derivatives 
have  been  identified  in  the  pus  from  liver  abscesses. 

Lesions. — The  liver  contains  suppinvative  centers  of 
varying  dimensions.  The  foci  may  occur  throughout 
the  entire  liver  and  be  microscopic  in  size,  causing  a 
uniform  enlargement  of  the  liver,  or  the  suppurative 
centers  may  be  as  large  as  walnuts  and  appear  as  small 
abscesses.  The  liver  will  be  engorged  with  blood,  more 
friable  than  normal,  and  it  may  be  variegated  in  color, 
due  to  alternating  small  hemorrhagic  areas  and  sup- 
purative foci.. 

Larger  suppurative  centers  are  gray  in  color  and  may 
or  may  not  be  circumscribed  by  a  capsule  of  fibrous 
tissue.  The  content  may  be  semifluid  pus  or  it  may  be 
caseous  or  even  calcified. 

Symptoms. — The  evidence  of  suppurative  hepatitis 
consists  of  general  depression.  The  animal  does  not 
move  of  its  o'wai  volition.  There  is  pain  on  palpation  of 
the  abdomen  (if  abdominal  walls  are  not  too  thick),  and 
icterus.  Less  extensive  suppuration  of  the  liver  may 
not  produce  any  distinct  symptoms. 

Treatment. — The  animal  should  be  made  as  com- 
fortable as  possible  and  the  evacuation  of  the  bowel 
content  facilitated  by  the  use  of  laxatives. 

Acute  Interstitial  Hepatitis 

Acute  interstitial  hepatitis  is  not  a  common  con- 
dition but  it  does  occur  in  swine  and  therefore  should 
receive  some  consideration. 

Etiology. ^ — The  cause  of  acute  interstitial  hepatitis 
probably  always  enters  the  liver  by  way  of  the  hepatic 
artery,  and  is  most  frequently  due  to  bacterial  infection 
or  animal  parasitic  invasion.  The  various  suppurative 
bacteria,  Bacillus  coli  communis  or  some  of  its  derivatives 
and  Bacillus  necrophorus,  may  be  the  causative  agent. 
Protozoan  parasites  and  the  larvae  of  some  vermes  are 
responsible  for  some  cases  of  acute  interstitial  hepatitis. 

Lesions. — The  liver  is  enlarged  and  appears  to  be 
affected   with   chronic   interstitial  hepatitis   because   the 


64  SWINE  DISEASES 

interlobular  tissue  is  infiltrated  with  leukocytes.  The 
liver  tissue  is  soft  and  friable.  Microscopic  study  of 
these  livers  has  revealed  the  fact  that  in  nearly  every 
instance  the  infiltration  leukocytes  are  practically  all 
eosinophiles. 

Symptoms. — Few  if  any  investigations  of  these 
cases  have  been  made  clinically  or  at  least  such  have 
not  been  reported.  The  marked  interlobular  infiltration 
tends  to  obstruct  the  biliary  capillaries,  causing  reab- 
sorption  of  bile  with  accompanying  icterus. 

Treatment. — The  nature  of  this  condition  permits 
of  little  if  any  relief  by  the  use  of  drugs.  Providing  the 
proper  diet  and  surroundings  are  provided,  treating  the 
symptoms  as  they  arise  is  apparently  all  that  can  be 
advised  for  the  relief  of  this  condition. 

Chronic  Interstitial  Hepatitis  (Cirrhosis-Sclerosis) 

Chronic  interstitial  hepatitis,  cirrhosis  or  sclerosis  of 
the  liver,  consists  of  a  proliferation  of  fibrous  tissue 
which  damages  and  ultimately  displaces  some  of  the 
functional  liver  tissue.  The  condition  is  rather  common, 
especially  in  swane  fed  upon  fermented  products,  such 
as  distillery  waste,  or  garbage. 

Etiology. — This  condition  is  due  to  injurious  chemical 
agents  derived  either  from  the  food  or  from  bacterial 
action,  that  is,  those  substances  that  are  capable  of 
producing  a  mild  degree  of  irritation.  Animal  para- 
sites, either  by  direct  mechanical  irritation  or  irritation 
by  eliminated  chemicals,  also  produce  chronic  inter- 
stitial hepatitis.  The  condition,  too,  may  be  secondary 
to  other  disease  processes. 

Lesions. — Chronic  interstitial  hepatitis  is  essentially 
a  })roliferation  of  fibrous  tissue.  The  fibrous  tissue  may 
be  produced  within  the  liver  lobule,  causing  an  enlarge- 
ment of  the  lobules  and  also  of  the  liver.  This  type  is 
designated  hypertrophic  sclerosis  of  the  liver.  Such  a 
liver  is  enlarged,  dense,  increased  in  weight,  lighter  in 
color,  and  when  cut  gives  the  impression  of  cutting 
fibrous   tissue.     In   other   instances   the   proliferation   of 


THE  DIGESTIVE  SYSTEM  65 

fibrous  tissue  occurs  in  the  interlobular  tissue  only. 
This  newly  formed  fibrous  tissue  later  contracts,  thus 
diminishing  the  size  of  the  affected  lobules,  and  there- 
fore the  liver  as  a  whole.  This  condition  is  termed 
atrophic  sclerosis.  Such  a  liver  usually  has  an  irregular 
outline  (hobnail  liver)  and  is  smaller,  denser,  and  lighter 
in  color  than  a  normal  liver.  It  is  possible  that  hyper- 
trophic sclerosis,  or  the  formation  of  new  fibrous  tissue 
throughout  the  entire  liver  lobule,  follows  when  the  irri- 
tant is  introduced  through  the  portal  vein,  and  atrophic 
sclerosis  occurs  when  the  irritant  is  introduced  through 
the  hepatic  artery. 

Symptoms.— Hepatic  sclerosis  has  an  insidious  onset. 
Probably  the  first  evidence  of  the  disease  is  digestive 
derangement,  which  later  may  be  accompanied  by 
icterus.  The  animals  become  unthrifty  and  finally 
weak  and  emaciated. 

Treatment. — Remove  the  cause  and  prevent  further 
progress  of  the  disease.  A  strict  diet  and  the  main- 
taining of  a  laxative  condition  of  the  bowel  may  permit 
the  affected  animals  to  be  gotten  into  condition  for 
slaughter. 

Tumors 

Hepatic  tumors  are  frequently  observed  by  veterinary 
inspectors  in  abattoirs,  but  these  tumors  are  rarely  of 
sufficient  magnitude  to  have  produced  visible  symptoms 
in  the  animal  prior  to  slaughter. 

The  various  kinds  of  tumors  that  have  been  observed 
in  the  liver  of  swine  are  true  to  the  type  for  the  same 
tumors  in  other  animals.  The  malignant  tumors  of  the 
liver  frequently  are  found  to  be  secondary-.  Of  the 
types  of  liver  tumors  the  following  have  been  identified, 
lipoma,  myxoma,  angioma,  sarcoma,  adenoma,  epi- 
thelioma, and  carcinoma. 

No  definite  symptoms  of  hepatic  tumors  can  be 
described;  often  there  is  no  outward  evidence.  There 
may  be  digestive  disorders,  emaciation,  and  evidence  of 
malnutrition. 


66  SWINE  DISEASES 

The  treatment  of  hepatic  tumors  in  swine  is  not 
practicable. 

Parasites 

Parasitic  invasion  of  the  liver  is  very  common  in 
swine.  The  result  of  hepatic  parasitism  has  not  attracted 
the  attention  of  the  clinician,  but  it  has  caused  con- 
siderable concern  with  the  inspectors  of  meat  and  food 
products.  In  the  middle  section  of  the  United  States 
the  livers  of  the  majority  of  swine  evidence  parasitism 
or  lesions  indicating  previous  parasitic  invasion  and 
activity.  Parasitic  conditions  of  the  liver  of  swine  are 
of  considerable  economic  importance  because  of  the  con- 
demnation, and  therefore  the  loss,  of  this  organ  as  a 
food  product. 

Coccidiosis 

Liver  abscesses  containing  Coccidia  have  been  ob- 
served. The  conditions  are  not  very  common.  Johne 
observed  in  swine  abscesses  as  large  as  an  apple  that 
contained  a  Coccidium  to  which  he  attributed  the 
cause. 

Stephanurosis 

It  is  rather  common  to  observe  lesions  in  the  liver  of 
swine  caused  by  the  Stephanurus  dentatum.  The  mode 
of  entrance  of  these  parasites  into  the  liver  may  be  by 
way  of  the  hepatic  duct,  through  the  portal  vein,  or  by 
direct  migration  from  the  peritoneal  cavity  through  the 
liver  capsule.  They  establish  inflammation  accompanied 
by  the  formation  of  pus  and  later  necrosis  of  the  liver 
tissue.  The  entire  lesion  is  surrounded  by  a  rather 
dense  white  fibrous  connective-tissue  capsule.  From 
one  to  three  of  the  parasites  are  found  in  the  necrotic 
purulent  material.  The  content  of  the  lesion  later 
becomes  caseous  and  may  ultimately  calcify. 

No  symptoms  have  been  observed  in  the  liver  that 
could  be  attributed  to  the  direct  action  of  the  Stephanurus. 

Remedial  treatment  is  not  available,  but  preventive 
measures  should  be  taken  to  avoid  future  disturbances. 


THE  DIGESTIVE  SYSTEM  67 

The  exact  life  cycle  of  the  parasite  is  not  known,  but 
general  sanitary  regulations  are  always  in  order  and 
will  no  doubt  be  of  value  in  preventing  or  at  least  dimin- 
ishing the  extent  of  future  infestations. 

Ascaridiasis 

An  occasional  ascarid  migrates  into  the  liver  by  way 
of  the  hepatic  duct.  These  parasites  in  this  location 
mechanically  obstruct  the  outflow  of  bile  and  also  pro- 
duce sufficient  local  irritation  to  establish  a  catarrhal 
inflammation  of  the  hepatic  duct,  the  gall  bladder,  or 
the  bile  duct. 

Icterus,  associated  with  digestive  derangement,  w^ill 
probably  be  the  only  evidence  of  the  presence  of  this 
parasite  in  any  portion  of  the  liver  or  its  excretory  duct. 

The  location  of  the  parasite  prohibits  the  successful 
use  of  therapeutic  agents.  The  possibility  of  invasion 
into  any  of  the  hepatic  structures  may  be  diminished  by 
frequent  medication  of  the  swine  with  agents  previously 
mentioned  that  will  eliminate  these  parasites  from  the 
bowel.  Frequent  cleaning,  and  removal  of  the  excrement 
from  the  pens,  yards,  or  barns,  ^ill  tend  to  diminish 
infestation. 

Distomatosis 

This  is  a  condition  resulting  from  the  invasion  of  the 
liver  by  the  Distoma  hepaticum,  Distoma  Americanum, 
or  Distoma  lanceclatum.  All  are  commonly  called  flukes. 
Distomatosis  occurs  most  frequently  in  animals  kept 
upon  low,  marshy,  or  swampy  lands.  Swine  raised  in 
the  southern  part  of  the  United  States  are  commonly 
infested.  The  exact  Ufe  cycle  of  these  parasites  has 
been  carefully  worked  out  and  may  be  obtained  by 
reference  to  works  on  parasites;  suffice  here  to  say  that 
the  ova  are  eliminated  from  the  liver  in  the  bile  and 
pass  to  the  outside  in  the  fecal  matter.  After  several 
changes  the  embryos  are  found  upon  vegetation  which 
is  consumed  by  their  hosts.  They  find  their  way  up 
the  hepatic  duct  and  on  into  the  bile  tubes  within  the 
liver. 


68  SWINE  DISEASES 

Lesions. — The  lesions  established  bj^  the  different 
types  of  Distoma  are  sHghtly  different.  The  Distoma 
hepaticum  remains  for  six  months  in  the  bile  tubes  in 
the  liver,  where  it  produces  obstruction  of  bile  and  inflam- 
mation of  the  bile  tubes.  The  accumulated  bile  causes 
distention  of  the  bile  tube,  which  is  usually  very  evident, 
particularly  upon  the  posterior  surface  of  the  liver.  The 
dilated  bile  tube  is  found  to  be  thickened  and  contains 
thickened  flocculent  bile  and  flukes  in  some  stage  of 
development,  depending  upon  the  length  of  time  after 
invasion  that  the  autopsy  is  conducted. 

The  Distoma  Americanum  either  remains  in  the  bile 
tubes  or  passes  out  into  the  substance  of  the  liver, 
where  it  produces  a  cyst.  These  cysts,  which  attain 
the  size  of  a  hen's  egg,  are  evidenced  by  grayish-black 
elevation  upon  the  surface  of  the  liver.  The  cysts 
contain  a  chocolate-colored  fluid  and  one  or  more  dis- 
tomes. 

The  Distoma  lanceolatum  produces  lesions  similar  to 
those  produced  by  the  Distoma  Americanum.  The 
latter  parasite  is  easily  distinguished  from  the  former  by 
its  large  size  and  its  distinctive  shape. 

A  Hver  in  which  the  Distoma  have  developed  and 
disappeared  contains  cicatrices  or  areas  of  necrotic 
calcareous  material,  evidences  of  the  parasitic  invasion. 

Symptoms. — It  is  difficult  to  diagnose  hepatic 
distomiasis  by  the  clinical  symptoms.  The  history  of 
the  case,  particularly  the  source  of  the  animal  affected, 
should  be  given  proper  consideration.  The  symptoms 
vary  according  to  the  intensity  of  infestation,  and  do 
not  appear  for  from  one  to  two  months  after  infestation. 
There  is  more  or  less  icterus,  digestive  derangement, 
unthriftiness,  and  emaciation.  The  disease  may  terminate 
fatally  and  it  may  be  quite  widespread,  affecting  a  large 
percentage  of  swine  in  the  Southern  States,  particularly 
during  wet  seasons. 

Treatment. — Treatment  is  of  no  avail.  Invasion 
may  be  diminished  or  entirely  prevented  by  keeping 
swine  out  of  pens,  yards,  and  pastures  where  previous 


THE  DIGESTIVE  SYSTEM  69 

infestation  has   occurred  and  by   properly   disposing  of 
the  excrements  of  swine  that  are  infested. 

Echinococcosis 

The  invasion  of  the  Hver  of  swine  with  the  larvae  of 
the  Teenia  echinococcus  is  quite  common.  In  the  Old 
A^'orld  from  one  per  cent  to  seventy  per  cent  of  the 
swine  are  reported  to  be  so  infested. 

The  mode  of  entrance  into  the  liver  is  by  way  of  the 
portal  system,  the  embryo  passing  through  the  intestine 
into  capillaries  that  empty  into  radicles  of  the  portal 
vein.  Infestation  is  derived  from  food  or  drink  con- 
taminated with  the  feces  of  dogs,  that  harbor  the  Taenia 
echinococcus. 

Lesions. — ^The  liver  is  enlarged;  the  degree  depending 
upon  the  number  of  parasitic  cysts  it  contains.  Gerard 
observed  an  infested  swine  liver  that  weighed  110  pounds. 
The  surface  of  the  liver  may  be  very  irregular  due  to 
the  presence  of  the  cysts  near  the  capsule  or  just  beneath 
the  capsule.  The  cysts,  which  vary  in  size  from  a  pear 
to  a  small  hen's  egg,  are  the  primary  lesions  and  may  be 
polymorphous  or  multilocular.  The  polymorphous  cysts 
are  surrounded  by  a  fibrous  capsule  inside  of  which  the 
true  cystic  membrane  is  found  and  upon  which  daughter 
and  granddaughter  cysts  and  the  head  of  the  future 
tapeworm  may  be  seen.  The  cyst  contains  a  pale, 
straw-colored,  limpid  serum.  The  multilocular  cyst  is 
a  mass  of  single  cysts  developing  on  the  outside  of  the 
true  cystic  membrane  instead  of  developing  on  the  inside, 
as  in  the  polymorphous  cyst.  The  cysts  necessarily  dis- 
place and  by  pressure  destroy  liver  tissue.  Old  cysts 
contain  a  cheesy  or  caseous  substance;  in  some  instances 
a    purulent    collection. 

Symptoms. — Clinical  evidence  of  the  presence  of 
hepatic  echinococcus  cysts  are  usually  wanting.  A  few 
cases  of  ascites  associated  with  hepatic  echinococcosis 
have  been  recorded.  There  may.be  icterus  and  some 
digestive  disturbance. 


70  SWINE  DISEASES 

Treatment. — Because  of  the  location  and  nature  of 
the  lesion,  treatment  for  echinococcosis  is  ineffectual. 
The  condition  is  readily  prevented  by  treating  with 
teniafuges  all  valuable  dogs  that  are  associated  in  any 
way  with  the  swine  and  by  destroying  all  worthless 
curs  and   properly  disposing  of  their  carcasses. 

Cysticercosis 

Hepatic  cysticercosis  of  swine  is  not  very  common. 
It  is  found  principally  in  young  pigs,  where  it  is  the 
result  of  invasion  of  the  liver  with  embryos  of  the  Taenia 
marginata  of  the  dog.  These  embryos  are  obtained 
in  food  that  has  been  contaminated  with  dog  feces. 
They  gain  entrance  to  the  liver  by  way  of  the  portal 
vein.  Some  of  the  embryos  pass  out  of  the  liver  in  the 
hepatic  vein;  others  bore  through  the  organ  and  its 
capsule  into  the  peritoneal  cavity. 

Lesions. — In  extensive  invasion  the  liver  is  enlarged. 
There  may  be  evidence  of  perihepatitis.  A  small  elevation 
may  occur  upon  the  surface  and  in  each  elevation  a 
small  opening  may  be  observed.  The  liver  is  of  a  varie- 
gated color,  due  to  alternating  areas  of  hemorrhage  and 
degeneration. 

Symptoms. — Unthriftiness,  weakness,  anorexia,  and 
increased  thirst  may  be  observed  in  hepatic  cystic- 
ercosis. The  affected  animals  may  become  rapidly 
emaciated;  there  may  be  evidence  of  peritonitis — and  in 
exceptional  cases  the  animals  may  die  suddenly,  but  as 
a  rule  they  linger  for  several  weeks. 

Treatment. — Symptomatic  treatment  maj'  be  re- 
sorted to,  but  it  is  doubtful  if  satisfactory  results  will  be 
obtained.  This  condition  may  be  prevented  by  the  proper 
treatment  or  disposal  of  dogs  as  recommended  under 
echinococcosis. 

.     PANCREAS 

Little  is  known  concerning  the  diseases  of  the  pan- 
creas. A  condition  known  as  multiple  fatty  necrosis 
occurs  in  swine  and  is  thought  to  be  the  result  of  obstruc- 


THE  DIGESTIVE  SYSTEM  71 

tion  to  the  outflow  of  pancreatic  juice.  Sarcomas 
involving  the  pancreas  in  swine  have  been  observed, 
but  they  were  evidently  not  primary  in  that  organ. 

PERITONEUM 

Defects  in  the  formation  of  the  peritoneum  are  not 
common.  Rarely  cystic  inclusions  or  exclusions  may  be 
observed. 

Injuries 

The  peritoneum  is  occasionally  injured  in  swine. 
The  injuries  may  be  inflicted  during  a  surgical  operation 
or  they  may  be  produced  accidentally.  The  result  of 
injury  of  the  peritoneum  varies  with  the  location  and 
the  extent  and  nature  of  the  injury;  which  may  consist 
of  a  bruise  of  the  peritoneum,  in  which  case  there  is  a 
local  inflammatory  disturbance;  a  puncture  of  the  peri- 
toneum, resulting  in  general  peritonitis;  or  a  laceration 
of  the  peritoneum,  permitting  eventration. 

The  results  of  violence  from  the  external  surface  are 
self-evident,  but  the  injuries  may  be  inflicted  by  foreign 
bodies  in  the  alimentary  canal.  In  such  cases  there  is 
more  or  less  of  digestive  derangement  and  local  or  general 
peritonitis. 

Treatment. — Medicinal  treatment  may  be  applicable 
when  the  peritoneum  is  intact,  but  in  lacerations  of  the 
peritoneum  surgical  interference  alone  is  of  value. 

Ascites 

Ascites  is  a  condition  resulting  from  the  accumulation 
and  retention  of  excessive  quantities  of  lymph  or  diluted 
lymph  in  the  peritoneal  cavity.  The  peritoneal  cavity 
is  in  reality  a  large  lymph  space. 

Ascites  is  very  rare  in  swine. 

Etiology. — Ascites  is  caused  by  an  excessive  out- 
pouring of  lymph  into  or  a  diminished  absorption  of 
lymph  from  the  peritoneal  cavity.  The  lymph  escapes 
from  the  blood  capillaries  in  .the  subserosa  on  to  the 
surface    of    the    peritoneum.       The    usual     causes     are 


72  SWINE  DISEASES 

obstructed  portal  circulation,  which  may  be  due  to 
disturbances  of  the  liver,  valvular  defects  of  the  heart, 
chronic  nephritis,  or  direct  pressure  upon  the  portal 
vein. 

Lesions. — Enlarged  abdomen,  due  to  the  accumulated 
fluid  in  the  peritoneal  cavity.  The  fluid  is  thin,  limpid, 
and  is  noncoagulable.  The  lesions  of  the  primary  cause 
may  also  be  observed. 

Symptoms. — A  pendulous  abdomen  associated  with 
digestive  disturbances  and  malnutrition  are  the  principal 
evidences  of  this  disease. 

Treatment.^ — Treatment  is  of  little  value.  Tem- 
porary relief  may  be  obtained  by  paracentesis  abdominis. 

Peritonitis 

Inflammation  of  the  peritoneum  is  not  of  as  common 
occurrence  in  swine  as  it  is  in  horses,  and  the  disease  is 
less  fatal  in  swine  than  it  is  in  most  other  animals. 

Etiology. — Injuries,  and  infection  following  par- 
turition, are  the  most  common  causes  of  porcine  peri- 
tonitis. Occasionally  an  ascarid  may  perforate  the  bowel 
and  establish  inflammation. 

Lesions. — Peritonitis  may  be  serous,  fibrinous,  hemor- 
rhagic, purulent,  septic,  or  tubercular;  local  or  general; 
acute  or  chronic.  The  lesions  will  vary  according  to 
the  type  of  inflammation.  There  is  first  tumefaction, 
congestion,  loss  of  gloss  of  surface,  and  exudation.  The 
serous  exudate  is  sticky,  serum-like,  and  may  be  tinged 
with  blood;  the  fibrinous  exudate  coagulates  and  causes 
adhesions ;  the  hemorrhagic  exudate  is  of  a  bloody  appear- 
ance; and  the  purulent  exudate  is  composed  of  pus. 
Septic  peritonitis  is  associated  with  the  accumulation  of 
a  putrid  material  upon  the  peritoneal  surface.  There 
may  also  be  evidence  of  injury,  or  metritis,  and  probably 
some  intestinal  content  in  the  peritoneal  cavity.  Chronic 
peritonitis  is  associated  with  the  proliferation  of  fibrous 
tissue  and  usually  greater  or  less  adliesions  of  the  visceral 
and  parietal  peritoneum. 


THE  DIGESTWE  SYSTEM  73 

Symptoms. — Acute  peritonitis  is  associated  with 
abdominal  pain,  the  severity  of  which  depends  upon  the 
extent  and  intensity  of  the  inflammation.  The  pain  may 
be  manifested  on  palpation  of  the  abdomen.  The 
affected  animals  have  a  "tucked  up"  appearance;  the 
appetite  is  diminished  or  perhaps  wanting.  There  is  a 
rise  of  temperature  and  a  rapid,  wiry  pulse.  The  animals 
are  uneasy  and  restless. 

Animals  affected  with  chronic  peritonitis  may  show 
some  digestive  derangement  or  there  may  be  no  evidence 
of  disease. 

Treatment. — Remove  the  cause,  and  the  further 
treatment  will  depend  upon  the  cause  and  nature  of  the 
lesions.  In  all  cases  the  bowel  movement  should  be 
diminished  or  inhibited  by  the  use  of  opiates.  If  the 
disease  is  the  result  of  injury,  surgical  interference  and 
the  rational  application  of  antiseptics  is  indicated.  If 
the  animals  eat  they  should  recei\'e  only  liquid  foods 
easy  of  digestion. 

Tumors 

Some  cases  of  peritoneal  tumors  in  swine  have  been 
reported.  The  fibroma  of  swine  is  usually  benign;  it 
may  be  tabular  or  pedunculated.  Sarcoma,  endothe- 
lioma, and  carcinoma  also  have  been  observed,  the  first 
being  the  most  common. 

The  above-mentioned  tumors  are  pathologically  iden- 
tical to  the  same  type  of  tumors  observed  elsewhere  in 
swine  or  in  other  animals,  and  they  produce  practically 
the  same  results,  with  the  possible  exception  that  the 
malignant  tumors  are  not  so  fatal  as  in  some  other 
animals,  particularly  in  the  human. 

Parasites 

The  cystic  form  of  the  Taenia  echinococcus  (echin- 
ococcosis) is  probably  the  most  common  parasitic  invader 
of  the  peritoneum  of  swine.  The  description  of  these 
cysts  will  be  found  under  the  consideration  of  parasites 
of  the  liver. 


74  SWINE  DISEASES 

The  Cysticercus  tenuicollis  is  occasionally  observed 
involving  the  peritoneum  of  swine,  although  in  the 
central  United  States  these  cysts  are  much  more  common 
in  sheep.  These  cysts  contain  only  one  tapeworm 
embryo,  differing  in  this  particular  from  the  cysts  of 
the  Taenia  echinococcus.  They  have  a  double  membrane, 
the  embryo  is  suspended  in  a  thin,  watery  fluid  that  fills 
the  cyst,  which  may  attain  the  size  of  an  English  walnut. 

Stephanurus  dentatum,  both  in  the  adult  and  larval 
stage,  may  be  found  in  relation  to  the  peritoneum.  The 
lesions  they  produce  in  the  peritoneum  are  the  same  as 
those  produced  by  this  parasite  elsewhere  in  the  body. 

The  Ascaris  suum  may  bore  through  the  intestine  and  be 
found  in  the  peritoneal  cavity.  As  they  pass  out  of  the 
intestine  they  carry  various  bacteria  with  them  and  pos- 
sibly also  permit  the  escape  of  some  intestinal  content 
which  is  always  teeming  with  bacteria.  Thus  infectious, 
usually  septic,  peritonitis  results. 


SECTION   II 


THE  RESPIRATORY  SYSTEM 

NOSE 

THE  habit  of  rooting  predisposes  the  snout  of  swine 
to  various  kinds  of  injury  regardless  of  the  fact 
that  this  organ  has  been  designed  for  such  pur- 
poses. Ringing  of  swine  produces  an  injury  that  in 
some  instances  is  difficult  to  correct. 

Epistaxis 

Nose  bleeding  is  not  a  disease  primarily,  but  is  usually 
a  symptom  of  some  other  disease  or  abnormal  condition. 
Epistaxis  occurs  rather  commonly  in  swine. 

Etiology. — ^True  epistaxis  is  a  result  of  the  escape  of 
blood  from  some  of  the  blood  vessels  of  the  nasal  chambers 
or  related  cavities.  It  is  a  very  common  symptom  in 
hog  cholera  and  swine  plague,  and  has  been  observed 
in  cases  of  anthrax.  The  condition  is  sometimes  asso- 
ciated with  ulceration  of  the  schneiderian  membrane 
regardless  of  the  cause  of  the  ulcers.  In  some  instances, 
it  may  be  due  to  mechanical  injuries  of  the  mucous 
membrane. 

Lesions. — Except  in  epistaxis  resulting  from  trauma, 
the  lesions  of  the  primary  condition  are  more  prominent 
than  those  associated  with  the  hemorrhage. 

Symptoms. — Escape  of  blood,  usually  from  the 
nostril,  is  the  principal  evidence  of  epistaxis.  The 
escaping  blood  may  be  scarlet  red  or  dark  red,  depending 
upon  whether  the  blood  is  escaping  from  an  artery  or  a 
vein.  Epistaxis  can  be  distinguished  from  pulmonary 
hemorrhage  by  the  fact  that  the  discharged  blood  from 
the  latter  is  frothy. 

75 


76  SWINE  DISEASES 

Treatment. — Epistaxis  is  usually  not  fatal.  It  is 
difficult  to  treat  in  swine  because  of  the  small  size  of  the 
opening  of  the  nostril.  Hydrogen  peroxide  may  be 
introduced  by  means  of  a  syringe,  and  this  gives  immediate 
and  sometimes  permanent  relief.  A  solution  of  adrenalin 
chlorid  gives  similar  results. 

Rhinitis 

Catarrhal  rhinitis  is  very  common  in  swine.  It  may 
be  either  acute  or  chronic. 

Etiology. — Catarrhal  inflammation  of  the  schneid- 
erian  membrane  is  most  commonly  caused  by  the  inliala- 
tion  of  dust  or  other  irritating  substances.  It  may  be 
caused  also  by  sudden  temperature  changes.  It  is 
sometimes  associated  with  other  disease  conditions, 
particularly  swine  plague  and  hog  cholera.  An  infec- 
tious type  of  this  disease  has  been  identified  and  is 
discussed  separately.     (See  p.  77.) 

Lesions. — Acute  catarrhal  inflammation  of  the  nasal 
mucosa  is  characterized  by  congestion  and  tumefaction 
of  the  mucous  membrane.  This  membrane  is  at  first 
dry,  but  later  varying  quantities  of  a  serous  fluid  and 
mucous  escape  upon  the  surface  of  the  mucosa  and  are 
discharged,  some  of  the  discharge  accumulating  upon 
the  external  surface  of  the  nostril.  The  exudate  may 
become  infected  and  invaded  by  leukocytes,  the  dis- 
charge thus  becoming  mucopurulent  or  purulent .  Chronic 
catarrhal  inflammation  may  produce  a  hypertrophy  or 
atrophy  of  the  nasal  mucosa.  The  hypertrophic  change 
is  due  to  the  production  of  ^rge  quantities  of  fibrous 
tissue  in  the  submucosa.  The  mucosa  thus  becomes 
thickened,  dense,  and  leathery.  The  increased  volume 
of  the  mucous  membrane  may  so  diminish  the  cavities  of 
the  nose  that  breathing  is  difficult.  In  other  instances 
the  mucous  membrane  atrophies,  the  nasal  cavity  thus 
becoming  larger.  It  is  not  unusual  to  find  desiccated 
discharges  adhering  to  the  mucosa.  In  either  the  hyper- 
trophic or  atrophic  forms  of  chronic  catarrhal  rhinitis 
there  may  be  ulceration  of  the  mucous  membrane.     When 


THE  RESPIRATORY  SYSTEM  77 

such  ulcers  occur  they  usually  involve  only  the  mucous 
membrane. 

Symptoms. — Discharge  from  the  nose  of  a  serous, 
mucous,  seromucous,  pus,  or  mucopurulent  material  is 
indicative  of  nasal  catarrh.  The  affected  animal  may 
sneeze  and  evidence  some  difficulty  in  breathing. 

Treatment. — Remove  the  cause,  and  if  the  condition 
has  not  persisted  until  it  is  chronic  there  will  usually  be  a 
speedy  recovery.  A  common  cause  of  catarrhal  rhinitis  is 
inhalation  of  dust,  and  therefore  dusty  pens  frequently 
contain  swine  with  nasal  catarrh.  The  condition  in  such 
cases  can  usually  be  checked  by  sprinkling  or  wetting 
the  pens.  Medicinal  treatment  is  not  of  great  value  for 
this  condition  in  swine  because  of  the  difficulty  of  its 
application.  Laxatives  may  be  of  some  value.  Those 
animals  affected  with  advanced  cases  of  the  chronic 
form  of  the  disease  had  best  be  put  into  a  marketable 
condition,  if  possible,  and  sold  for  slaughter. 

Infectious  Nasal  Catarrh 

An  infectious  nasal  catarrh  of  swine  occurs  enzootically 
in  Germany  It  usually  confines  its  ravages  to  pigs  less 
than  six  months  of  age.  A  similar  clinical  affection 
occurs  in  some  sections  of  the  United  States,  but  in  this 
country  the  specific  causative  agent  has  not  been  identi- 
fied. 

Etiology. — In  1906,  the  Bacillus  pyocyaneus  was 
identified  by  Koske  as  the  causative  factor,  although  the 
infectious  nature  of  the  disease  was  recognized  as  early  as 
1890.  The  Bacillus  pyocyaneus  is  found  in  manure 
heaps  and  mulched  soils;  it  gains  entrance  to  the  nose 
while  the  swine  are  rooting  and  is  readily  transmitted 
from  a  diseased  to  a  healthy  animal  by  means  of  the 
nasal  discharges. 

Lesions. — This  disease  is  characterized  by  an  intense 
inflammation  which  causes  a  marked  congestion  of  the 
mucosa  and  not  infrequently  a  hemorrhagic  inflammation. 
The  lesions  extend  and  involve  the  sinuses  and  the 
ethmoidal  cells,  and  there  may  be  involvement  of  the 


78  SWINE  DISEASES 

optic  and  olfactory  nerves,  of  the  cerebral  meninges,  and 
of  the  brain  itself.  The  usual  lesions  in  the  last-mentioned 
structures  consist  of  hemorrhages  beneath  the  sheath  of 
the  optic  and  olfactory  nerves,  congestion  of  the  meninges, 
and  edema  of  the  cerebral  tissue  proper.  Various  changes 
may  be  observed  in  other  internal  organs  as  a  result  of 
high  temperature  and  possibly  also  of  metastasis  of  the 
infecting  agent. 

Symptoms. — High  temperature  and  inappetence  are 
usually  the  first  symptoms  of  the  disease.  Sneezing, 
and  vigorous  rooting  or  rubbing  the  nose,  are  followed  by 
epistaxis,  edema  of  the  snout,  and  difficult  breathing. 
The  affected  animals  may  be  blind  in  one  or  both  eyes, 
and  if  there  is  meningeal  involvements  the  pigs  will 
evidence  extreme  excitement  and  finally  die  in  a  comatose 
state.  The  disease  may  result  fatally  in  a  very  short 
time,  its  course  in  the  most  fatal  epizootics  being  from 
three  to  six  days.  A  chronic  or  less  fatal  form  has  been 
observed  in  which  the  course  of  the  disease  varies  from 
one  week  to  several  weeks,  and  some  of  the  animals  may 
recover. 

Treatment. — In  the  acute  form  of  infectious  nasal 
catarrh  treatment  has  not  been  successful.  From  the 
experience  of  those  veterinarians  where  this  disease  pre- 
vails it  seems  best  to  recommend  destruction  of  all  affected 
animals.  An  antitoxin  may  be  prepared  and  used  to 
offset  the  injurious  influences  of  the  toxic  substances 
produced  and  eliminated  by  the  Bacillus  pyocyaneus. 
Prophylactic  sanitary  measures  should  be  instituted  and 
rigidly  enforced  on  premises  where  this  disease  abounds. 

Tumors 

Various  tumors  have  been  observed  in  the  nasal 
cavity  of  swine  or  involving  some  related  structure. 
Almost  all  of  these  tumors  have  been  of  the  benign  type 
and  therefore  interfere  only  mechanically.  Pedunculated 
fibromas  are  not  so  common  in  swine  as  in  some  other 
animals. 


THE  RESPIRATORY  SYSTEM  79 

LARYNX 

Laryngitis 

Inflammatory  disturbances  of  the  larynx  are  relatively 
common  in  swine  but  are  not  of  sufficient  gravity  to 
warrant  a  lengthy  discussion. 

Etiology. — Undue  exposure  and  inhalation  of  sus- 
pended or  gaseous  irritants  are  common  causes  of  laryn- 
gitis. In  swine,  as  in  other  animals,  laryngitis  is  rarely 
a  distinct  process  but  is  a  condition  associated  with 
inflammatory  disturbances  of  the  pharynx,  or  trachea, 
and  therefore  the  inflammatory  process  of  the  larynx  is 
frequently  an  extension  from  an  adjacent  structure. 
Chronic  laryngitis  results  from  the  same  causative  factors 
as  the  acute  type,  being  merely  extended  over  a  longer 
period. 

Lesions. — Laryngitis  in  swine  is  generally  of  a 
catarrhal  type  and  may  be  either  acute  or  chronic,  al- 
though an  occasional  case  of  croupous  laryngitis  occurs. 
The  lesions  observed  are  practically  identical  with  the 
usual  lesions  of  this  type  of  inflammation. 

Symptoms. — The  principal  symptom  of  laryngitis  is 
a  cough,  which  is  at  first  dry,  later  moist,  and  always 
painful.  The  cough  may  become  convulsive.  In  the 
intense  acute  attacks  there  will  be  rise  of  temperature 
and  probably  inappetence.  By  palpation  the  laryngeal 
region  will  be  found  supersensitive. 

Treatment. — Provide  sanitary  surroundings  and  if 
the  patient  is  inclined  to  eat,  give  sparingly  of  easily 
digested  slops.  Medicinal  treatment  is  so  difficult  to 
apply  that  frequently  more  harm  than  good  is  the  result. 

Tumors 

Laryngeal  tumors  are  rare.  However,  pedunculated 
fibromas  have  been  observed,  and  epithelioma  has  been 
reported. 


80  SWINE  DISEASES 

TRACHEA 

Malformations 

A  case  occurs  occasionally  in  which  the  esophagus 
forms  a  union  with  the  trachea.  Pigs  so  affected  usually 
die  soon  after  farrowing. 

Stenosis 

Congenital  stenosis  may  occur  in  swine,  but  is  rela- 
tively rare.  Acquired  stenosis  is  also  rare,  because  of 
the  protection  of  the  trachea  from  external  injuries. 

Tracheitis 

This  inflammatory  disturbance  is  usually  associated 
with  laryngitis  or  bronchitis,  and  partakes  so  closely  of 
the  nature  of  these  latter  affections  that  further  descrip- 
tion will  not  be  given. 

Tumors 

Tracheal  tumors  are  not  common  in  swine,  though 
fibromas  and  myxomas  of  the  benign  tumors  have  been 
observed. 

BRONCHIAL  TUBES 

The  principal  malformations  of  the  bronchial  tubes 
consists  of  an  irregularity  in  the  distribution  of  the 
branches  of  those  tubes,  but  as  a  rule  this  produces  little 
or  no  inconvenience  to  the  animal  and  is  therefore  of 
scientific  interest  only. 

Stenosis 

Bronchial  stenosis  is  relatively  common  in  swine. 
The  condition  may  affect  either  the  large  or  small  tubes. 
Bronchial  stenosis  is  probably  most  frequently  the  result 
of  a  diseased  condition  of  the  bronchial  mucosa,  such  as 
catarrhal  inflammation,  ulceration,  tuberculosis,  para- 
sitic invasion,  or  mechanical  injury  due  to  some  foreign 
body,  as  a  needle  or  a  nail. 


THE  RESPIRATORY  SYSTEM  81 

Bronchitis 

The  principal  inflammatory  disturbance  of  the 
bronchial  tubes  is  of  a  catarrhal  nature,  at  least  in  the 
beginning.  Catarrhal  bronchitis  may  be  either  acute  or 
chronic. 

Etiology.— Undue  exposure  to  inclement  weather  is 
one  of  the  principal  causes  of  bronchitis.  Inhalation  of 
dust-laden  air  is  also  an  important  causative  factor  of 
inflammation  of  the  bronchial  tubes.  Infection  is  in 
many  instances  an  auxiliary  of  other  causes  and  the 
Bacilli  necrophorous  and  pyocyaneus  are  many  times  the 
primary  causes  of  bronchial  catarrh.  This  condition  may 
be  associated  with  other  diseases,  such  as  swine  plague 
or  hog  cholera. 

Chronic  bronchial  catarrh  results  from  the  action  of 
the  same  causative  factors  that  produce  acute  catarrh, 
but  the  irritants  are  usually  less  intense  and  act  for  a 
longer  time. 

Lesions. — ^There  is  congestion  of  the  affected  mucosa, 
which  later  becomes  covered  with  mucous  or  with  a 
mucopurulent  discharge.  In  extreme  cases  the  discharge 
may  be  tinged  with  blood  and  become  purulent.  When 
the  disease  process  involves  the  capillary  bronchial  tubes 
there  is  usually  more  or  less  of  emphysema,  due  to  obstruc- 
tion of  the  tubes  with  exudate  which  prevents  the  escape 
of  air  from  the  air  cells.  There  may  be  areas  of 
atelectasis  which  project  beyond  the  surface  of  the  lung 
and  are  of  a  darker  color  than  the  lung. 

Chronic  bronchial  catarrh  is  characterized  by  the 
presence  of  mucous,  purulent,  or  even  caseous  material 
in  the  bronchial  tubes,  and  by  fibrous  proliferation  in 
the  submucosa  which  may  result  in  an  attenuation  of 
the  mucosa.  Dilatation  or  bronchiectasis  is  a  common 
lesion,  particularly  in  the  dependent  parts  of  the  lung,  in 
chronic  catarrhal  bronchitis.  In  long-standing  cases 
there  may  be  peribronchitis,  evidenced  by  fibrous  pro- 
liferation around  the  bronchial  tubes,  which  may  extend 
into  the  pulmonary  tissue. 


82  SWINE  DISEASES 

Symptoms. — The  principal  symptom  of  bronchitis 
is  a  cough  which  in  the  beginning  is  dry  but  later  becomes 
moist.  The  cough  may  become  convulsive.  As  the 
disease  progresses  a  nasal  discharge  becomes  evident, 
which  is  at  first  of  the  nature  of  mucus  but  later  becomes 
mucopurulent  or  purulent.  Rales  may  be  detected  in 
thin  swine,  or  possibly  in  any  of  the  bacon  breeds,  but  the 
chest  wall  of  other  swine  is  usually  so  thick  that  it  prac- 
tically prohibits  the  recognition  of  pulmonary  conditions. 
There  is  usually  some  rise  of  temperature  in  the  beginning, 
but  this  may  subside.     The  appetite  may  be  diminished. 

Treatment.  —  Removing  the  cause  and  providing 
sanitary  surroundings  will  probably  do  more  than 
medication  to  relieve  this  condition.  Supply  easily 
digested  foods.  If  the  swine  can  be  controlled  easily  and 
placed  in  a  piggery  that  can  be  made  practically  airtight, 
the  animals  may  be  successfully  treated  with  medicated 
vapors,  using  such  agents  as  oil  of  eucalyptus. 

Verminous  Bronchitis  and  Pneumonia 

Verminous  bronchitis  is  very  common  in  swine  in  the 
United  States;  however,  the  infestation  is  only  rarely  of 
sufficient  extent  to  produce  serious  damage.  The  lungs 
from  a  thousand  swine  were  inspected  in  a  Kansas  City 
abattoir  and  sixty  per  cent  of  them  contained  pulmonary 
Strongyli  in  such  numbers  that  the  lesions  could  readily 
be  observed  by  gross  examination. 

Etiology. — Metastrongylus  apri  is  the  causative 
parasite  of  porcine  pulmonary  strongylosis.  It  is  a 
white  or  brownish-white  thread-like  worm  from  one  inch 
to  one  and  a  half  inches  in  length.  The  adults  inhabit 
the  middle-sized  and  small  bronchioles,  usually  in  the 
posterior  superior  part  of  the  lung,  although  they  may  be 
found  elsewhere  in  the  lung.  The  ova  are  carried  out 
from  the  lung  in  the  discharge  and  may  pass  out  directly 
or  pass  into  the  pharynx  and  be  eliminated  in  the  feces. 
The  exact  life  cycle  is  not  known,  but  it  is  probable  that 
the  ova  hatch  and  undergo  several  moults  before  regaining 
the  animal  body.     The  parasites  gain  entrance  to  the 


THE  RESPIRATORY  SYSTEM  83 

animal  body  in  the  food  or  water,  infestation  of  swine 
being  easily  accomplished.  Young  pigs  are  most  sus- 
ceptible; however,  the  parasites  have  been  identified  in 
swine  of  all  ages.  After  the  parasites  gain  entrance  to 
the  animal  body  they  begin  to  migrate,  some  of  them 
ultimately  reaching  the  bronchial  tubes.  The  exact 
route  of  migration  is  still  a  disputed  question,  but  they 
pass  either  by  way  of  the  pharynx  through  the  larynx 
to  the  bronchial  tubes,  by  way  of  the  blood  stream,  or 
directly  through  the  tissues. 

Lesions. — The  principal  lesions  in  swine  are  found 
in  the  posterior  lobes  and  in  the  superior  part  of  those 
lobes.  At  first  the  lesions  are  confined  to  centers,  or 
foci,  which  are  cone-shaped  and  usually  atelectatic, 
though  they  may  protrude  and  be  of  a  doughy  con- 
sistency. In  a  later  stage  these  foci  are  found  to  contain 
mucopurulent,  purulent,  or  even  caseous  substances  in 
varying  quantities  in  addition  to  from  one  to  many 
Strongyli  and  their  ova.  Similar  discharges  will  be 
found  in  the  bronchial  tubes  and  even  in  the  trachea, 
and  occasionally  disintegrated  vermes  and  their  ova  will 
be  found  in  the  expectorate.  There  may  be  bronchiec- 
tasis, but  this  condition  is  not  common.  The  visceral 
pleura  may  show  evidence  of  chronic  inflammation. 

Symptoms. — The  period  of  incubation  varies  from 
four  to  eight  weeks.  Although  this  condition  is  very 
prevalent,  the  infestation  is  usually  limited  and  fatalities 
from  this  disease  are  exceptional.  The  primary  symptom 
is  a  cough,  which  usually  involves  several  animals  at  once 
and  becomes  more  frequent  as  the  disease  progresses. 
In  fatal  or  severe  cases  the  cough  is  paroxysmal,  the 
animals  sometimes  falling  to  the  ground  from  exhaustion 
and  lack  of  air.  A  sticky,  adhesive  discharge  prevails 
and  accumulates  upon  the  nostrils,  respiration  becomes 
difficult,  and  a  distinct  wheezing  sound  can  be  heard. 
The  temperature  may  be  increased  from  one  to  three 
degrees  Fahrenheit.  Emaciation  is  rapid.  Edema  of 
the  dependent  parts  occurs,  and  the  animals  become 
weak  and  finally  die  of  exhaustion.     The  course  of  the 


84  SWINE  DISEASES 

disease  varies  from  one  to  three  or  four  months.  The 
diagnosis  should  be  based  upon  the  history  of  the  out- 
break, the  number  of  animals  involved,  the  character  of 
the  cough,  and  finally  upon  the  detection  of  ova  and 
parasites  in  the  discharges  and  the  presence  cf  parasites 
in  the  lungs  on  autopsy. 

Treatment. — This  disease  is  difficult  to  treat  because 
of  the  location  of  the  parasites  and  the  difficulty  of  con- 
trolling swine.  The  only  rational  method  consists  of 
the  intratracheal  injections  of  some  agent  that  will 
destroy  the  parasites,  or  by  the  inhalation  of  medicated 
vapors.  These  methods  are  not  easily  adapted  to  the 
treatment  of  swine,  particularly  the  intratracheal  injec- 
tions. Medicated  vapors  may  be  used,  providing  the 
swine  can  be  confined  in  an  airtight  room. 

Further  infestation  should  be  prevented  by  the  proper 
disposal  of  the  various  excretions  from  the  infested 
animals.  The  pens  should  be  thoroughly  cleaned  and 
some  efficient  parasiticide  applied.  If  the  infestation  is 
in  pasture  land,  it  will  be  necessary  to  cliange  pasture, 
keeping  all  swine  away  from  the  known  infested  pasture 
for  at  least  a  year,  and  for  two  years  if  possible. 

LUNGS 

Atelectasis 

This  is  a  condition  of  collapse  of  the  lung;  the 
absence  of  air  in  the  lung,  and  may  be  either  congenital 
or  acquired.  The  lung  of  the  fetus  is  always  atelectic 
before  birth.  This  is  one  means  of  determining  a  still 
birth,  and  is  often  useful  as  evidence  in  legal  cases. 
Partial  congenital  atelectasis  may  be  the  result  of  obstruc- 
tion of  a  bronchus  with  meconium  or  mucus;  it  may  also 
be  the  result  of  excessive  extrathoracic  pressure.  Acquired 
atelectasis  may  be  due  to  compression  of  the  lung  by 
inflammatory  exudate  (pleuritic  effusions),  edematous 
transudate,  or  forward  displacement  of  the  diaphragm. 
It  mav  also  be  due  to  obstruction  of  the  bronchus,  the 


THE  RESPIRATORY  SYSTEM  85 

air  contained  in  the  air  cells  being  absorbed  and  per- 
mitting them  to  collapse. 

Lesions. — The  affected  lung  tissue  collapses  and  does 
not  crepitate.  It  is  red  or  reddish-brown  in  color,  feels 
dry,  is  tough,  and  sinks  in  water.  If  the  condition  is 
of  long  standing,  the  affected  area  becomes  darker  in 
color  and  is  designated  cornification.  In  some  instances 
the  atelectic  areas  become  spleen-like,  due  to  the  develop- 
ment of  fibrous  tissues,  and  this  is  termed  splenization. 

Atelectasis  diminishes  the  breathing  capacity,  which 
is  the  only  symptom  characterizing  the  condition.  Small 
areas  of  the  lung  will  not  produce  visible  symptoms. 
This  condition  is  usually  associated  with  other  disease 
processes,  the  symptoms  of  which  mask  those  of  atelec- 
tasis. 

Atelectasis  occurs  in  the  lung  of  swine  as  a  result  of 
swine  plague,  hog  cholera,  bronchitis,  pneumonia,  and 
pleurisy,  as  well  as  of  other  less  important  diseases. 

Emphysema 

Pulmonary  emphysema  has  been  observed  in  swine 
but  is  not  of  common  occurrence.  It  is  due  to  con- 
ditions that  favor  the  inflation  of  the  lung  with  excessive 
quantities  of  air.  Bronchopneumonia  is  occasionally 
associated  with  emphysema.  The  affected  areas  are 
soft,  spongy,  anemic,  and  project  beyond  the  surface  of 
the  lung. 

Edema 

Pulmonary  edema  is  not  common  in  swine  kept  under 
ordinary  conditions,  but  it  is  often  found  in  those  that 
are  hyperimmunized  for  the  production  of  anti-hog- 
cholera  serum.  Those  haAing  experience  as  serum  pro- 
ducers occasionally  have  a  swine  die  of  pulmonary 
edema  at  the  time  or  immediately  after  the  intravenous 
injection  of  quantities  of  virulent  blood. 

In  comparison  to  their  size,  swine  have  a  relatively 
small  lung.  The  virulent  blood  that  is  used  in  hyper- 
immunizing  is  defibrinated  but  contains  both  the  red  and 


86  SWINE  DISEASES 

white  blood  cells,  some  of  which  are  disintegrated.  Large 
quantities  of  tliis  defibrinated  blood,  containing  cor- 
puscles in  various  stages  of  disintegration  as  well  as  the 
virus,  are  introduced  into  an  ear  vein.  The  first  capillary 
system  it  would  pass  through  is  in  the  lung  where,  no 
doubt,  more  or  less  obstruction  of  capillaries  is  effected 
and  the  virus,  or  some  chemical  ingredient  of  the  blood, 
may  cause  an  increased  permeability  of  the  blood  vessels 
and  facilitate  the  outpouring  of  the  serum. 

Lesion. — The  lungs  are  engorged  with  blood.  The 
air  cells  contain  varying  quantities  of  serum,  the  lung 
thus  becoming  soggy  and  edematous.  No  other  lesion 
of  any  significance  is  found. 

Symptoms. — The  affected  animal  at  first  becomes 
restless  and  uneasJ^  There  is  increased  respiration, 
soon  followed  by  dyspnea,  cessation  of  breathing,  and 
death.  In  some  cases  all  these  symptoms  occur  within 
a  few  minutes  and  during  the  time  that  the  virus  is  being 
introduced.  If  the  injection  is  stopped  instantly  when 
the  first  symptom  becomes  evident  some  of  the  affected 
swine  will  recover,  but  in  some  of  them  the  various 
symptoms  occur,  succeeded  by  death,  even  though  the 
introduction  of  virus  be  stopped  when  the  first  symptom 
appears.  An  occasional  case  occurs  where  the  swdne 
will  show  no  discomfiture  at  the  time  of  the  injection  of 
the  virus,  but  may  be  found  in  distress  from  a  few  minutes 
to  an  hour  later.  In  such  cases,  death  will  usually 
result. 

Treatment. — Thus  far  no  treatment  has  been  found 
that  appears  to  be  of  value.  It  is  possible  that  centri- 
fuging  the  virus  will  overcome  the  difficulty. 

Hemorrhage 

Pulmonary  hemorrhage  is  not  common  in  swine  as 
a  primary  disease.  It  has  been  reported  as  occurring  in 
fattened  swine  that  are  driven  to  market,  especially 
when  they  become  very  hot.  It  is  rather  common  as  a 
secondary  condition  in  acute  cases  of  pneumonia,  swine 
plague,  and  hog  cholera. 


THE  RESPIRATORY  SYSTEM  87 

Cause. — Engorgement  of  the  lung  capillaries,  due  to 
overexertion,  excessive  heat,  or  disease,  is  the  chief 
cause  of  hemorrhage.  Weakening  of  the  vessel  walls 
due  to  malnutrition,  which  occurs  in  some  infective 
diseases,  is  another  cause. 

Lesions. — Almost  all  cases  of  hemorrhage  of  the 
air  passages  posterior  to  the  larynx  are  designated 
hemoptysis,  or  pulmonary  hemorrhage,  and  it  is  difficult 
in  some  instances  to  differentiate  tracheal  or  bronchial 
hemorrhage  from  pulmonary  hemorrhage.  If  the  hemor- 
rhage is  primary  the  escaped  and  escaping  blood  is 
practically  all  that  will  be  observed.  The  blood  that 
escapes  from  the  lung  or  smaller  bronchial  tubes  will 
contain  more  entangled  air,  that  is,  be  more  frothy  than 
that  coming  from  the  large  bronchi  and  the  trachea. 
In  secondary  pulmonary  hemorrhage  the  lesions  of  the 
primary  disease  will  also  be  evident. 

Symptoms. — If  the  extra vasate  is  limited  in  quantity 
it  may  be  absorbed  and  no  visible  symptoms  become 
evident.  Escape  of  frothy  blood  from  the  nose  and 
mouth  characterizes  hemoptysis.  In  cases  where  there 
are  large  quantities  of  blood  escaping  there  will  be  more 
or  less  bronchial  obstruction  and  consequently  difficult 
breathing,  and  the  animal  may  become  weak  from  loss 
of  blood.  The  condition  may  terminate  fatally  or  the 
affected  animal,  in  those  cases  where  the  hemorrhage  is 
limited,  may  recover. 

Treatment. — Keep  the  affected  animals  cool,  and 
where  they  will  be  least  excited. 

Pneumonia 

Inflammation  of  the  lung  is  not  of  common  occurrence 
in  swine  as  a  primary  condition  but  it  is  frequently 
associated  with  some  other  disease. 

Practically  all  types  of  pneumonia  based  upon  patho- 
logic classification  occur  in  swine.  The  following  types 
will  be  described:  catarrhal,  croupous,  purulent,  and 
gangrenous. 


88  SWINE  DISEASES 

Catarrhal  Pneumonia 

Catarrhal  pneumonia  is  a  lobular  involvement  char- 
acterized by  occlusion  of  the  air  cells,  with  exudate  and 
desquamated  epithelium. 

Etiology.^ — Catarrhal  pneumonia  is  practically  always 
a  sequel  of  bronchitis  and  is  therefore  produced  by  the 
same  causative  factors.  Bacillus  pyocyaneus  may  cause 
catarrhal  pneumonia.  Catarrhal  pneumonia  is  one  of 
the  characteristic  lesions  of  swine  plague  due  to  the 
Bacterium  suisepticus.  (Description  will  be  found  in 
Chapter  VIII.)  Bronchopneumonia  is  occasionally  sec- 
ondary to  other  diseases,  such  as  hog  cholera  or  septi- 
cemia. 

Lesions. — The  inflammatory  process  is  confined  to 
a  lobule  or  a  group  of  lobules.  As  the  disease  progresses, 
other  adjacent  lobules  may  become  involved,  the  affected 
areas  thus  becoming  confluent  and  larger.  In  the 
beginning  the  affected  areas  are  hyperemic.  The  alveoli 
soon  become  filled  with  inflammatory  exudate  which  is 
at  first  fluid  but  later  coagulates  and  becomes  dry,  the 
diseased  lobules  thus  becoming  solid.  These  areas  are 
first  red  in  color,  but  early  become  brown,  gray,  then 
yellow  or  yellowish-white,  and  if  the  condition  persists 
abscess  formation  may  occur.  Bronchitis  is  usually 
associated  with  bronchopneumonia  and  in  such  cases  the 
lesions  characterizing  bronchitis  would  also  be  present. 

Symptoms. — Catarrhal  pneumonia  in  swine  is  ex- 
tremely difficult  to  differentiate  from  bronchitis  because 
of  the  inability  to  efiiciently  auscultate  or  percuss  the 
thorax.  Catarrhal  pneumonia  offers  the  same  general 
symptoms  that  have  been  noted  in  bronchitis,  except 
that  pneumonic  symptoms  are  usually  more  intensive 
than  those  of  bronchitis.  Catarrhal  pneumonia  has  no 
definite  course,  the  length  or  duration  of  the  disease 
depending  upon  the  cause,  extent  of  the  disease,  and  the 
resistance  of  the  affected  animal.  The  disease  is  most 
fatal  in  young  swine. 

Treatm.ent. — Medicinal  treatment  other  than  in- 
halation  of  medicated  vapors  is  of  little  or  no  value. 


THE  RESPIRATORY  SYSTEM  89 

Proper  sanitary  conditions  should  be  provided,  and  the 
affected  animals  should  be  given  easily  digested,  whole- 
some food  in  sufficient  quantities  to  build  up  the  body 
and  maintain  strength.  If  the  causative  factor  is  an 
infection,  isolation  and  proper  quarantine  regulations 
should  be  enforced. 

Croupous  Pneumonia 

Croupous  pneumonia  is  a  disease  involving  lobes  or 
large  lung  areas  and  is  characterized  by  the  presence  of 
a  hemorrhagic  exudate  in  the  air  cells.  It  is  not  a  common 
primary  condition  in  swine,  but  is  frequently  associated 
with  hog  cholera. 

Etiology.- — Many  predisposing  factors  enter  into  the 
causation  of  this  disease,  such  as  undue  exposure  or 
inhalation  of  irritating  gases,  but  it  is  probable  that  the 
specific  active  cause  is  microbian. 

Lesions. — Croupous  pneumonia  is  characterized  by 
the  regularity  of  the  successive  changes  that  occur  in  the 
affected  portion  of  the  lung.  The  disease  usually  involves 
the  dependent  part  of  the  lung  and  is  essentially  lobar, 
but  more  or  less  than  t^his  amount  of  lung  may  be  involved. 
The  various  stages  that  occur  in  the  lung  are  as  follows: 
congestion,  red  hepatization,  gray  hepatization,  and 
resolution.  These  stages  occur  in  the  order  mentioned, 
and  there  is  no  distinct  line  of  demarcation  between 
each  succeeding  stage.  The  length  of  duration  of  each 
stage  is  subject  to  variation,  but  on  the  whole  is  quite 
constant.  The  congestive  stage  is  of  about  twenty-four 
hours'  duration.  During  this  stage  the  affected  portion 
of  the  lung  is  engorged  with  blood.  In  the  beginning 
the  air  cells  contain  air  but  as  the  disease  progresses 
the  alveolar  capillaries  begin  to  leak  or  there  is  a  hemor- 
rhagic exudate  into  the  alveoli.  Red  hepatization  begins 
when  exudation  is  evident,  and  this  stage  persists  for 
from  three  to  five  days;  the  area  affected  is  red,  dense, 
heavy,  and  liver-like.  Gray  hepatization  is  characterized 
by  a  gray  or  yellow  coloration  of  the  affected  lung.  This 
stage  succeeds  red  hepatization  and  is  due  in  part  to  the 


90  SWINE  DISEASES 

substitution  of  leukocytes  for  the  coagulated  hemorrhagic 
exudate  that  characterizes  red  hepatization  and  in  part 
to  chemical  change  of  the  hemoglobin  of  the  extra vasated 
red  blood  cells  in  the  hemorrhagic  exudate.  The  lung 
tissue  affected  with  gray  hepatization  is  gray  in  color, 
dense,  heavy,  and  cuts  like  liver  tissue.  Gray  hepatiza- 
tion persists  for  from  three  to  five  days,  and  when  the 
alveoli  are  relatively  free  of  exudate  and  leukocytes  the 
lung  is  said  to  be  in  a  stage  of  resolution,  which  includes 
that  period  of  time  during  which  the  air  cells  are  freed  of 
all  inflammatory  products  and  return  to  the  normal 
condition.  This  is  a  variable  period  and  depends  upon 
the  resistance  of  the  affected  animals.  The  lung,  during 
this  stage,  contains  some  inflammatory  products  in  the 
beginning  and  later  small  quantities  of  mucous  and 
debris,  but  in  the  final  stages  the  lung  is  practically 
normal. 

Symptoms. — Inappetence,  high  temperature,  and 
increased  respiration  and  heart  action  characterize 
croupous  pneumonia.  On  the  second  or  third  day  a 
"prune- juice"  nasal  discharge  may  be  observed  which 
later  becomes  mucous  or  mucopurulent.  The  affected 
swine  are  dull,  listless,  and  will  probably  cough  more  or 
less  when  agitated. 

Treatment. — Sanitary  surroundings,  good  water  to 
drink,  and  an  abundance  of  fresh  air  without  drafts  are 
prerequisites  in  the  treatment  of  pneumonia.  Laxatives 
should  be  given  to  prevent  constipation.  Heart  stimu- 
lants may  be  required,  but  should  not  be  administered 
except  when  necessary,  as  indicated  by  a  rapid,  weak 
pulse. 

Purulent  Pneumonia 

Purulent  pneumonia  is  an  inflammation  of  the  lung 
characterized  by  the  formation  of  pus.  This  condition 
is  relatively  common  in  young  pigs,  although  it  may 
occur  in  swine  of  any  age. 

Etiology. — Purulent  pneumonia  is  of  bacterial  origin. 
The    pyogenic    Micrococci,    BaciUus    pyocyaneus,    and 


THE  RESPIRATORY  SYSTEM  91 

tubercle  bacillus  are  the  most  frequent  causative  factors 
of  this  condition.  These  organisms  may  be  inhaled 
direct  but  they  are  more  frequently  introduced  into  the 
lung  from  elsewhere  as  emboli.  Purulent  pneumonia  in 
old  swine  is  therefore  frequently  associated  with  pyemia, 
abscess  formation,  or  purulent  metritis.  Several  cases 
have  been  observed  in  the  carcasses  of  swine  that  had 
previously  been  hyperimmunized  intramuscularly  for  the 
production  of  anti-hog-cholera  serum. 

Lesions. — ^The  principal  lesion  is  suppuration,  the 
centers  of  which  vary  in  size  and  number  but  in  the 
beginning  are  relatively  small  and  in  the  earlier  stages  are 
not  encapsulated  but  are  surrounded  by  a  zone  of  lung 
tissue  intensely  infiltrated  \\'ith  cells.  As  the  condition 
progresses  a  circumscribing  capsule  is  formed  and  the 
pus  becomes  thicker,  and  if  the  capsule  is  not  destroyed 
the  contained  pus  becomes  caseous  and  may  later  become 
calcified.  Should  the  capsule  of  a  suppurative  center 
become  eroded  -the  contained  pus  may  infiltrate  the 
adjacent  lung  tissue  or  discharge  into  a  bronchial  tube, 
the  original  suppurative  center  thus  becoming  a  cavity. 
The  pleura  covering  superficial  suppurative  centers 
usually  shows  some  involvement. 

Symptoms. — The  evidence  of  purulent  pneumonia 
varies  according  to  the  nature  and  extent  of  the  lesions. 
The  presence  of  a  single  abscess  may  not  cause  any 
noticeable  symptoms.  General  embolic  purulent  pneu- 
monia is  characterized  by  intense  symptoms  consisting  of 
chills,  fever,  difficult  and  hurried  breathing,  uneasiness, 
and  general  distress.  The  discharge  of  pus  within  the 
lung  tissue  is  evidenced  by  rise  of  temperature  and  the 
associated  cardiac  and  respiratory  disturbances. 

Treatment. — No  special  line  of  treatment  is  of 
value.  The  animals  should  be  placed  in  good  quarters 
and  cared  for  properly. 

Septic  or  Gangrenous  Pneumonia 

Septic  pneumonia  is  relatively  common  in  swine.  It 
has    occurred   enzootically   in   swine   affected   primarily 


92  SWINE  DISEASES 

with  forage  poisoning  associated  with  pliaryngeal  paraly- 
sis.    Sometimes  it  is  a  sequel  to  croupous  pneumonia. 

Etiology. — The  usual  cause  of  septic  pneumonia  is 
the  introduction  of  foreign  substances  into  the  lung.  In 
cases  of  pharyngeal  paralysis  food  escapes  into  the  air 
tube.  Drenching  is  another  means  by  which  foreign 
substances  are  frecjuently  introduced  into  the  lung. 
Thrombic  obstruction  of  vessels  supplying  an  area 
affected  with  croupous  pneumonia  favors  the  action  of 
saprophytic  bacteria,  and  hence  putrefaction  and  the 
production  of  septic  pneumonia.  Abscesses  sometimes 
become  infected  with  putrefying  organisms  and  produce 
septic  pneumonia.  The  Bacillus  necrophorous  is  active 
in  the  production  of  necrosis  and  putrefaction  in  the  lung. 

Lesions. — Necrotic  centers  are  most  frequently  found 
in  the  dependent  and  anterior  part  of  the  lung.  The 
foci  vary  in  size  from  that  of  a  pea  to  a  baseball,  and 
may  be  few  or  many.  They  appear  dirty  brown,  red, 
or  dirty  white  in  color.  When  incised  they  are  found  to 
be  soft,  the  content  being  semifluid  in  the  early  stages 
but  later  of  a  cheesy  consistency.  The  surrounding 
lung  tissue  will  be  inflamed.  In  the  beginning,  an 
infiltration  circumscribes  the  lesions,  but  in  the  older 
lesions  there  may  be  a  distinct  capsule.  Superficial 
necrotic  foci  may  be  associated  with  pleurisy. 

Symptoms. — The  first  symptom  evidencing  septic 
pneumonia  is  the  foul-smelling  exhaled  air.  This  symptom 
does  not  occur  in  all  cases,  as  the  escape  of  putrid  odors  is 
dependent  upon  the  erosion  and  discharge  into  the  bron- 
chial tubes  of  necrotic  putrid  material.  Rise  of  tempera- 
ture accompanies  practically  all  cases  of  septic  pneumonia. 
The  fever  may  be  irregular  and  intermittent,  the  thermal 
disturbance  depending  upon  absorption  of  septic  j)roducts. 
In  those  cases  of  croupous  pneumonia  in  which  septic 
pneumonia  is  a  sequel,  the  general  symptoms  will  be  the 
same,  plus  the  offensive  breath,  as  those  observed  in  a 
case  of  croupous  pneumonia  A  microscopic  examination 
of  the  nasal  discharge  will  reveal  the  presence  of  shreds 
of  disintegrated  lung  tissue  in  cases  of  septic  pneumonia, 


THE  RESPIRATORY  SYSTEM  93 

which  fact  is  of  diagnostic  vahie.  The  course  of  septic 
pneumonia  is  uncertain.  The  attack  may  terminate 
fatally  in  two  or  three  days  after  the  onset  of  the  disease 
or,  if  the  septic  lesions  are  limited  in  extent,  they  may 
become  encapsulated  and  the  animal  recover,  the  length 
of  time  required  varying  from  a  few  weeks  to  as*  many 
months. 

Treatment. — Remedial  agents  are  of  little,  or  no 
value  so  far  as  the  septic  process  is  concerned.  The 
treatment  of  symptoms  as  they  develop  will  be  of  some 
value.  The  animal  should  be  given  good  care  and 
sanitary  surroundings  provided. 

Interstitial  or  Chronic  Pneumonia 

Interstitial  pneumonia  is  a  chronic  condition  char- 
acterized by  proliferation  of  fibrous  tissues.  This  con- 
dition is  usually  a  sequel  to  chronic  catarrhal  bronchitis 
and  chronic  bronchopneumonia.  It  is  observed  in  swine 
in  those  sections  of  the  country  where  it  is  continuously 
dusty  and  in  swine  kept  in  quarters  where  slightly  irri- 
tating gases  prevail. 

Etiology. — Constant  inhalation  of  mild  irritants,  such 
as  dust  or  chemical  fumes. 

Lesions. — Fibrous  proliferation  characterizes  this 
disease.  The  fibrous  tissue  forms  around  the  bronchioles, 
the  process  gradually  extending  and  involving  the  alveoli. 
The  bronchioles  and  alveoli  also  show  evidence  of  catarrh. 
The  affected  lung  is  dense,  and  when  cut  offers  more 
resistance  than  the  normal  lung.  The  degree  of  fibrous 
proliferation  is  quite  variable  in  some  instances;  there  is. 
a  limited  amount,  and  in  other  cases  the  normal  lung 
tissue  is  displaced  by  fibrous  tissue.  Encapsulated 
suppurative  or  necrotic  centers  may  be  found. 

Symptoms. — A  persistent  cough,  associated  with  a 
limited  but  variable  nasal  discharge  of  a  mucopurulent 
material,  characterizes  chronic  pneumonia.  The  animals 
are  usually  unthrifty  and  emaciated. 

Treatment. — The  cause  should  be  removed  and  the 
animals  properly  housed  and  fed.  Other  than  this,  little 
can  be  done. 


94  SWINE  DISEASES 

Tumors 

Various  tumors  have  been  encountered  in  the  lungs 
of  swine,  but  principally  in  autopsies  or  at  abattoirs. 
Lung  tumors  of  swine  are  similar  to  the  same  type  of 
tumors  of  other  tissues.  Pulmonary  neoplasms  produce 
no  typical  symptoms  by  which  they  may  be  recognized 
clinically. 

Parasites 

The  principal  pulmonary  parasite  is  the  Metastrongy- 
lus  Apri,  which  has  been  described  under  bronchial 
disorders. 

Echinococcosis  pulmonum  is  a  common  disease  of 
swine.  This  condition  is  caused  by  the  larval  form  of 
Taenia  echinococcus.  The  cysts  of  pulmonary  echinococ- 
cus  are  the  same  as  those  occurring  in  the  liver. 

Distomiasis,  or  invasion  of  the  lung  with  flukes  or 
Distoma,  occurs  but  is  not  common  in  swine. 

Pulmonary  stephanurosis  has  also  beerj.  observed,  but 
is  rare. 

Parasitic  nodules,  the  supposed  result  of  invasion  of 
some  unknown  parasite,  are  occasionally  noted  by 
veterinary  inspectors,  .but  there  is  little  significance  in 
such  invasion  as  the  lung  is  not  edible,  according  to  the 
meat-inspection  regulations  in  the  United  States. 

PLEURA 

Disease  conditions  of  the  pleura  of  swine  are  rarely 
recognized  clinically,  though  some  cases  of  pleuro- 
pneumonia may  be  determined  by  a  clinical  examination. 
Pathologic  conditions  of  the  pleura  are  occasionally 
observed  by  veterinary  inspectors  in  the  carcasses  of 
swine  that  are  slaughtered. 

Hydrothorax 

Hydrothorax  is  a  condition  resulting  from  the  accumu- 
lation in  the  thoracic  cavity  of  excessive  quantities  of 
serous  fluid.     It  is  of  rather  rare  occurrence  in  swine. 


THE  RESPIRATORY  SYSTEM  95 

Etiology. — Obstructed  outflow  of  blood  from  the 
vena  cava,  with  engorgement,  is  the  principal  cause  of 
hydrothorax.  Chronic  disease  of  the  cardiac  valves  and 
chronic  pneumonia  are  the  most  common  causes  of 
obstruction  of  the  outflow  of  venous  blood  from  the 
vena  cava.  Tumors,  abscesses,  and  malformed  thorax 
may  also  be  responsible  for  the  causation  of  pneumo- 
thorax. 

Lesions. — Accumulation  of  varying  quantities  of  a 
pale  yellow  fluid  in  the  thorax  is  the  characteristic  lesion, 
and  in  addition  the  primary  lesions  in  the  heart  or  lung 
are  usually  evident.  The  accumulated  fluid  will  com- 
press the  lung. 

Symptoms. — It  is  not  possible  in  the  beginning  to 
detect  any  particular  symptoms.  Those  produced  by 
the  accumulated  fluid  are  frequently  so  overshadowed 
bj'  the  primary  condition  that  it  is  not  possible  to  clini- 
caUy  diagnose  hydrothorax  until  the  advanced  stages. 
There  will  be  difficult  respiration,  and  if  the  thoracic 
wall  is  not  too  thick  a  splashing  sound  may  be  noted 
synchronous  with  the  heartbeat.  An  exploratory  punc- 
ture with  a  small  hypodermic  needle  will  usually  result  in 
the  discharge  of  serous  fluid. 

Treatment. — Temporary  relief  may  be  obtained  by 
withdrawing  the  fluid  from  the  cavity,  but  permanent 
results  cannot  be  expected  until  the  primary  causative 
factor  has  been  removed  or  overcome. 

Hemothorax 

Hemothorax  is  a  condition  of  the  escape  and  accumu- 
lation of  blood  in  the  thoracic  cavity.  It  is  not  a  recog- 
nized clinical  entity,  particularly  in  relation  to  swine, 
yet  it  does  occur,  and  is  sometimes  observed  by  inspectors 
of  meat-food  products. 

Etiology. — This  condition  is  observed  in  swine  that 
have  been  transported  to  market,  and  the  affected  swine 
at  the  time  of  autopsy  show  evidence  of  having  been 
injured,  probably  while  in  transit.  The  injury  may  be 
a  puncture,  wound,  or  a  contusion. 


96  SWINE  DISEASES 

Lesions. — Accumulation  of  blood  in  the  thorax 
characterizes  this  condition.  The  blood  may  be  coagu- 
lated, but  it  usually  remains  in  the  fluid  state  until  the 
thorax  is  opened.  The  quantity  of  blood  will  depend 
upon  the  nature  of  the  injury  and  the  length  of  time 
elapsing  after  its  infliction.  If  the  hemorrhage  is  of 
long  standing,  pigmentation  of  the  pleura  may  be  the 
only  evidence  remaining. 

Symptoms. — ^The  majority  of  animals  affected  with 
hemothorax  show  no  symptoms.  There  may  be  paleness 
of  the  visible  mucous  membranes,  weakness  of  the  animal, 
and  diflScult  breathing  due  to  compression  of  the  lung, 
but  these  symptoms  are  evident  only  in  those  cases 
in  which  the  hemorrhage  is  extensive. 

Treatment. — Medicinal  treatment  is  of  no  value. 

Pneumothorax 

This  is  characterized  by  the  accumulation  of  air  in  the 
thoracic  cavity,  a  condition  extremely  rare  in  swine. 
The  usual  cause  of  the  condition  is  injury  in  which  the 
lung  tissue  is  lacerated.  The  injury  most  frequently 
consists  of  fracture  of  a  rib  occasioned  by  improper  hand- 
ling in  transportation. 

The  principal  lesion  observed  consists  of  the  primary 
injury.  The  thorax  is  found  to  contain  air,  and  the  lung 
is  compressed. 

Pleurisy 

Pleurisy  is  inflammation  of  the  pleura  and  may  be 
serous,  fibrinous,  hemorrhagic,  or  purulent;  acute  or 
chronic.  It  is  not  a  common  condition  among  swine,  at 
least  in  so  far  as  the  clinical  recognition  of  it  is  concerned. 

Acute  Pleurisy 

Etiology.— Acute  pleurisy  is  practically  always  the 
result  of  infection,  although  there  are  many  predisposing 
factors  that  are  active  in  diminishing  resistance  and  thus 
increasing   the   possibility   of   successful   infection.     The 


THE  RESPIRATORY  SYSTEM  97 

causative  organisms  may  gain  entrance  to  the  pleura 
from  the  hmgs  through  puncture  wounds,  through  the 
blood,  and  through  the  lymph. 

Lesions. — The  pleura  becomes  hyperemic,  tumefied, 
and  dry.  This  stage  is  succeeded  by  an  outpouring  of  a 
serous,  fibrinous,  or  hemorrhagic  exudate  upon  the 
pleural  surface.  Should  the  disease  be  due  to  the  activity 
of  pyogenic  organisms  the  exudate  will  soon  become 
purulent,  and  the  future  changes  depend  upon  the  nature 
of  the  exudate.  Serous  exudate  may  accumulate  in 
quantities  in  the  pleural  cavity,  and  remain  fluid 
although  it  may  contain  flakes  of  coagula.  The 
fibrinous  and  hemorrhagic  exudates  coagulate  early  and 
produce  greater  or  less  adhesion  of  the  visceral  and 
parietal  pleura.  The  hemorrhagic  exudate  is  characterized 
by  the  presence  of  quantities  of  hemoglobin,  which 
gives  to  it  a  red  or  blood  color. 

Chronic  Pleurisy 

Chronic  pleurisy  is  characterized  by  the  formation  of 
varying  quantities  of  fibrous  tissue  which  produce  per- 
manent adhesions  of  the  two  layers  of  the  pleura.  There 
may  also  be  considerable  quantities  of  a  fluid  (serous) 
exudate  in  the  pleural  cavity,  and  there  may  be  abscess 
formation,  the  pus  being  circumscribed  by  a  definite 
capsule. 

Symptoms  • — Difficult  breathing,  each  effort  being 
accompanied  by  a  grunt,  and  sensitiveness  of  the  thorax, 
characterize  pleurisy.  In  the  acute  cases  there  is  inap- 
petence,  high  temperature,  and  usually  constipation. 
Chronic  cases  frequently  show  little  evidence  of  dis- 
turbance. 

The  acute  type  has  a  relatively  short  course,  ter- 
minating in  recovery,  or  in  death  "^-ithin  a  few  days. 
The  chronic  form  may  persist  for  weeks  or  even  months. 

Treatment. — Remove  the  cause  of  the  trouble  and 
establish  sanitary  conditions.  The  treatment  of  symptoms 
as  they  arise  will  be  of  some  value.      If  an  excessive 


98  SWINE  DISEASES 

quantity  of  serous  fluid  accumulates  in  the  pleural  cavity 
it  should  be  withdrawn. 

Tumors 

Pleuritic  tumors  are  not  common  in  swine.  Fibromas 
have  .been  encountered  on  a  few  occasions.  Of  the 
malignant  tumors,  endothelioma  and  sarcoma  pre- 
dominate, but  are  unusual. 


SECTION   III 
THE  URO-GENITAL  SYSTEM 

SWINE  are  prone  to  various  disease  conditions  of 
the    organs    constituting    the    uro-genital    system. 
This  may  be  due  to  the  nature  of  their  food  stuff, 
which  is  often  fermented  or  putrid. 

KIDNEYS 

Kidney  diseases  are  especially  common  in  swine. 
Frequently  the  pathologic  condition  of  the  kidney  is  not 
of  sufficient  intensity  to  produce  recognizable  symptoms, 
but  a  diseased  condition  is  easily  detected  by  autopsy  or 
on  inspection  of  the  carcasses  of  dressed  hogs. 

Malformations 

There  may  be  a  total  absence  of  one  or  the  other 
kidney.  A  horseshoe-shaped  kidney  is  also  occasionally 
observed.  Floating  kidney  has  been  reported,  but  from 
the  number  of  recorded  cases  the  condition  is  relatively 
rare. 

Hydronephrosis 

Hydronephrosis,  or  cystic  kidney,  is  of  frequent 
occurrence  in  swine.  It  is  very  commonly  encountered 
by  the  food  inspector.  Tucks  reported  0.67  per  cent  of 
cystic  kidneys  in  over  six  thousand  hogs  examined,  and 
the  writer  found  this  condition  in  the  kidneys  of  twenty- 
nine  swine  in  three  thousand  examined.  The  condition 
may  affect  one  or  both  kidneys. 

Etiology. — Obstructed  outflow  of  urine  is  the  primary 
cause  of  cyst  formation  in  the  kidney.  The  anatomical 
arrangement  of  the  openings  of  the  ureters  into  the 
bladder  predisposes  to  their  obstruction  and  therefore  to 
the  accumulation  of  urine  in  the  kidney  pelvis.  Renal 
and  pelvic  calculi  and  inflammatory  products  occasion 

99 


100  SWINE  DISEASES 

obstruction  of  collecting  tubules  and  favor  cyst  formation. 
Cicatrization  of  newly  formed  fibrous  tissue  may  obstruct 
the  outflow  of  urine  and  cause  cyst  formation.  Complete 
obstruction  of  the  ureters  or  kidney  pelvis  will  not  as  a 
rule  result  in  hydronephrosis,  as  this  condition  results  in 
a  compensatory  activity  on  the  part  of  the  normal 
kidney. 

Lesions. — Hydronephrosis  may  occur  as  cysts  in  the 
renal  substance  or  the  kidney  may  be  practically  replaced 
by  a  variable-sized  watery  bag.  The  cysts  vary  in  size 
from  a  pinhead  to  an  inch  in  diameter.  There  may  be 
myriads  of  the  small  cysts  scattered  throughout  the 
kidney  but  occurring  primarily  in  the  cortical  portion. 
The  larger  cysts  are  usually  not  numerous  and  they 
frequently  represent  the  fusion  of  small  cysts.  The  cysts 
have  a  bluish-white  color,  are  definitely  surrounded  by  a 
distinct  capsule,  and  the  content  is  thin  and  watery. 
The  kidney  substance  between  the  cysts  is  atrophied, 
due  to  pressure.  In  extreme  cases  the  kidney  capsule 
may  serve  as  the  cystic  capsule,  the  entire  mass  being 
much  enlarged  and  the  small  atrophied  kidney  floating 
within.  Richter  reported  a  case  of  a  hydronephrotic 
kidney  weighing  over  ninety  pounds. 

Hemorrhage 

Kidney  hemorrhage  is  relatively  common  in  swine, 
not  as  a  primary  condition,  but  associated  with  some 
disease.  The  extra vasated  blood  may  escape  into  the 
uriniferous  or  collecting  tubules,  producing  hematuria, 
or  it  may  escape  into  the  kidney  tissue. 

Etiology. — Injury  of  the  capillaries,  either  glomerular 
or  tubular,  may  result  in  hemorrhage.  The  vessels  are 
most  frequently  damaged  by  chemical  substances  that 
are  being  eliminated  in  the  urine  or  by  products  of 
bacteria  produced  in  the  kidney  or  elsewhere  in  the 
body. 

[  Lesions. — Escaped  blood  into  the  uriniferous  tubules 
may  be  detected  by  examination  of  the  urine,  which,  by 
the  way,  is  very  infrequently  done.     The  urine  will  be 


THE  URO-GENITAL  SYSTEM  101 

discolored  with  hemaglobin  and  will  contain  blood  casts. 
Renal-tissue  hemorrhages  may  be  extensive  or  limited, 
but  rarely  is  extensive  extravasation  observed  in  the 
kidney.  Small-tissue  hemorrhages,  particularly  petechial 
hemorrhages,  are  of  common  occurrence  in  the  kidney  of 
swine  affected  with  hog  cholera.  Such  hemorrhages 
have  been  observed  in  the  kidney  of  otherwise  apparently 
healthy  swine  in  which  no  other  lesions  of  cholera  could 
be  detected,  and  tlie  blood  from  these  hogs,  when  injected 
into  healthy,  susceptible  pigs,  failed  to  produce  evidence 
of  hog  cholera.  These  hemorrhages  were  not  numerous; 
sometimes  only  a  very  few  could  be  recognized  by  a 
careful  examination;  their  exact  relation  has  not  been 
discovered.  The  petechial  hemorrhage  of  cholera  merely 
evidences  a  vascular  disturbance. 

Symptoms. — Hematuria  indicates  hemorrhage  into 
the  urine  in  the  kidney,  ureter,  bladder,  or  urethra.  Renal 
hematuria  is  characterized  by  bloody  urine  and  the 
presence  of,  blood-tube  casts. 

Fatty  Changes 

The  occurrence  of  the  so-called  large  white  kidney  is 
a  common  experience,  at  least  to  those  engaged  in  meat 
inspection.  "Large  white  kidney"  is  a  name  applied  to 
two  different  conditions — fatty  kidney  and  fibrous  kidney. 
The  fatty  white  kidney  is  less  common  than  the  fibrous 
white  kidney. 

Etiology. — Some  renal  vascular  disturbance  resulting 
in  blood  disturbance  in  the  kidney  or  general  malnutrition 
appears  to  be  the  causative  factor  in  the  production  of 
fatty  kidneys. 

Lesions. — The  affected  kidney  is  large  and  creamy 
white  in  color.  The  capsule  is  easily  stripped,  and  the 
kidney  substance  is  soft  and  feels  greasy.  Only  one 
kidney  is  affected  in  those  cases  in  which  the  kidney  is 
exceedingly  large.  Both  kidneys  may  be  affected,  but 
to  a  limited  degree. 

Symptoms. — No  primary  symptoms  characterize 
this  condition.     It  is  detected  only  in  autopsy. 


102  ,  SWINE  DISEASES 

Calculi 

Renal  calculi  occur  but  are  not  common  in  swine. 
They  may  occur  in  the  collecting  tubules  but  are  more 
likely  to  be  found  in  the  renal  pelvis. 

Etiology. — The  formation  of  renal  calculi  is  usually 
associated  with  an  obstructed  outflow  of  urine.  Retained 
urine  in  the  renal  pelvis  or  in  the  collecting  tubules  has  a 
tendency  to  undergo  fermentation,  with  the  production 
of  an  unl)alanced  condition  of  the  chemical  constituents 
resulting  in  precipitation.  Retained  urine  and  fermenta- 
tion also  favors  catarrhal  inflammation.  The  muco- 
purulent discharge  may  serve  as  a  nucleus  upon  which 
the  precipitate  is  deposited. 

Lesions. — Retention  of  urine  and  catarrhal  inflam- 
mation are  usually  evident.  The  calcular  deposits  may 
be  very  small  and  difficult  to  detect  or  they  may  be 
quite  large,  one  having  been  observed  that  practically 
filled  the  renal  pelvis.  The  calculi  may  be  variable  in 
shape,  color,  and  consistency,  depending  upon  their 
composition,  and  are  composed  of  magnesium  or  calcium 
phosphates,  urates,  or  carbonates. 

Symptoms. — Cloudy  urine,  particularly  when  the 
last  discharge  contains  quantities  of  brownish  deposit, 
will  be  observed  if  the  calculi  are  passing  out.  The 
animals  will  have  colicky  pains,  the  loins  will  be  sensitive, 
and  the  animals  will  stand  with  arched  back.  If  the 
calculi  are  small  and  remain  in  the  kidney  there  may  be 
no  evident  symptoms. 

Treatment. — If  the  patient  is  in  good  condition  it 
will  be  most  economical  to  sell  it  for  slaughter.  Very 
little  can  be  done  toward  the  actual  solution  of  the 
formed  calculi. 

Congestion 

Congestion  of  the  kidneys  is  common  in  swine  fed  on 
putrid  or  fermented  foods.  It  may  occur  as  a  result  of 
undue  exposure,  to  cold  experienced  in  shipping,  or  it 
may  be  due  to  injury.  The  condition  is  associated  with 
erysipelas,  hog  cholera,  and  some  forms  of  pneumonia. 


THE  URO-GENITAL  SYSTEM  103 

Etiology. — Chemical  poison  obtained  in  food,  by- 
products of  infection,  or  destructive  metabolism  cause 
renal  congestion.  Exposure  and  injury  may  also  produce 
this  condition. 

Symptoms. — Stiffness  and  a  stilty  gait  due  to 
hypersensitiveness  of  the  loins  usually  accompany  con- 
gestion. There  is  also  frequent  urination  in  which  an 
excessive  quantity  of  urine  is  voided. 

Treatment. — Remove  the  cause,  give  good  food, 
and  provide  sanitary  surroundings.  Alkaline  diuretics 
may  be  of  value,  and  laxatives  may  also  be  used  to 
advantage. 

Nephritis 

It  is  not  possible  with  the  present  available  knowledge 
to  classify  the  inflammatory  disturbances  of  the  kidney 
in  a  satisfactory  manner.  The  principal  knowledge  of 
porcine  nephritis  has  been  obtained  from  investigation 
by  veterinarians  in  food-inspection  service.  The  con- 
dition is  rarely  recognized  clinically,  or  at  least  the 
reports  of  clinical  cases  of  nephritis  in  swine  are  very 
rare.  Urinalysis  is  not  practiced  systematically  by 
veterinarians,  and  the  analysis  of  swine  urine  by  prac- 
titioners is  practically  an  unheard-of  procedure.  Accord- 
ing to  the  findings  of  the  veterinary  inspectors,  porcine 
nephritis  is  very  common.  In  some  instances  nephritis 
appears  to  be  the  only  pathologic  condition  existing,  but 
it  is  also  an  accompanying  pathologic  factor  in  such 
diseases  as  hog  cholera,  swine  plague,  septicemia,  and 
pneumonia. 

Acute  Parenchymatous  Nephritis 

This  is  an  inflammation  of  the  cells  of  the  glomeruli 
and  convoluted  tubules  and  is  characterized  by  a  rather 
rapid  onset,  tumefaction,  and  frequently  destruction  of 
the  affected  epithelium. 

Etiology. — Exposure  to  cold  and  injuries  of  various 
kinds  predispose  to  this  disease.  The  specific  exciting 
causes  are  usually  chemical  substances  that  are  being 
eliminated     through     the     renal     epithelium.     Bacterial 


104  SWINE  DISEASES 

products,  and  vegetable  and  mineral  poisons,  when 
present  in  sufficient  quantities,  are  capable  of  establishing 
inflammation.  Thus  pneumonia,  hog  cholera,  swine 
plague,  and  septic  infections  are  usually  accompanied  by 
nephritis.  Some  serum  producers  have  had  losses  of 
hyperimmune  swine  due  to  contaminated  virus.  In  the 
swine  that  died  in  these  cases  not  only  the  lesions  evi- 
dencing general  septic  infection  were  present  but  also 
marked  lesions  of  an  acute  parenchymatous  nephritis. 
Turpentine,  phenol,  and  the  various  coal-tar  products  are 
capable  of  producing  nephritis.  Corrosive  sublimate, 
too,  may  be  obtained  in  sufficient  quantities  to  produce 
the  disease. 

Lesions. — The  lesions  of  acute  parenchymatous 
nephritis  are  practically  confined  to  the  epithelium  of  the 
glomeruli  and  convoluted  uriniferous  tubules.  The 
affected  kidney  is  slightly  enlarged  and  has  a  parboiled 
appearance.  The  capsule  is  easily  removed,  the  kidney 
substance  is  usually  soft,  and  blood  escapes  freely  from  a 
cut  surface.  Microscopically  the  affected  epithelium  is 
affected  with  hyperemia  and  cloudy  swelling  which  may 
become  so  intensive  that  the  cells  undergo  necrosis.  The 
detritis  of  the  dead  cells  and  coagulated  exudate,  accumu- 
lated in  the  lumina  of  the  tubules,  may  be  readily  ob- 
served. The  intertubular  tissue  may  be  infiltrated  with 
leukocytes.  If  the  inflammation  is  intense  there  may  be 
hemorrhage  into  the  kidney  substance  or  into  the  glom- 
eruli or  tubules. 

Symptoms.- — The  animals  show  evidence  of  dis- 
tress. One  of  the  first  indications  of  the  disease  is  arched 
back  and  stilty  gait.  There  are  frequent  attempts  at 
urination,  but  little  urine  is  voided,  and  the  animals  usually 
have  a  temperature  ranging  from  104  to  106  degrees 
Fahrenlieit.  In  the  beginning  of  the  attack  they  may 
eat,  but  inappetence  becomes  evident  soon  after  the 
onset.  It  is  possible  that  the  foregoing  symptoms  are  not 
characteristic  of  uncomplicated  nephritis,  but  of  cases  in 
which  nephritis  was  the  most  prominent  condition.  In 
the   cases   that  have  been   observed   the   disease   most 


THE  URO-GENITAL  SYSTEM  105 

frequently  terminated  fatally  in  from  two  to  four  days 
after  the  onset,  the  few  cases  that  recovered  requiring 
from  one  to  six  weeks. 

Treatment. — The  treatment  of  nephritis  in  swine  is 
a  difficult  problem.  Resort  should  be  had  to  the  usual 
hygienic  practices.  Diaphoresis  is  not  practical  in  swine, 
and  purgation  should  not  be  resorted  to  as  a  means  of 
ehmination,  for  such  procedure  would  probably  aggravate 
the  condition  existing  in  the  kidney.  General  treatment 
of  symptoms  as  they  arise  is  probably  all  that  can  be 
accomplished  therapeutically  until  further  knowledge  is 
obtained. 

Acute  Interstitial  Nephritis 

An  occasional  kidney  is  found  in  which  there  is  a 
leukocytic  invasion  and  other  evidence  of  a  reaction  in 
the  interstitial  or  supporting  tissue,  the  parenchymatous 
tissue  being  unaffected.  But  this  condition  is  not  com- 
mon, and  thus  far  has  not  been  observed  chnically  in 
swine. 

Purulent   Nephritis 

Purulent  nephritis  is  inflammation  of  the  kidney 
characterized  by  the  formation  of  pus,  a  condition  of 
frequent  occurrence  in  swine.  In  the  study  of  swine 
kidneys  from  abattoirs  one-half  of  one  per  cent  have 
been  found  affected. 

Etiology.— Pyogenic  cocci  and  the  colon  bacteria  are 
the  most  common  causative  agents.  Purulent  inflam- 
mation elsewhere  in  the  body  predisposes  to  renal  meta- 
stasis, although  purulent  inflammation  may  occur  pri- 
marily in  the  kidney  Constipation  is  probably  a  pre- 
disposing factor  of  colon-bacillus  invasion  of  the  kidney. 

Lesions. — Suppuration  may  be  circumscribed,  thus 
forming  an  abscess  or  multiple,  abscesses,  or  it  may  be 
diffuse.  Metastatic  purulent  nephritis  usually  involves 
both  kidneys,  and  small  suppurative  centers  occur  as 
gray  or  yellow  areas  which  are  surrounded  by  a  hyperemic 
zone.  The  larger  foci  may  be  quite  definitely  circum- 
scribed   and    frequently    have    small    bands    of    fibrous 


106  SWINE  DISEASES 

tissue  extending  from  the  capsule  into  the  purulent 
center.  Microscopically  the  small  centers  are  found  in 
the  beginning  to  be  collections  of  leukocytes  and  later  of 
pus.  The  surrounding  parenchymatous  tissue  will  be 
affected  with  cloudy  swelling,  as  in  acute  parenchymatous 
nephritis. 

Symptoms. — Practically  the  same  symptoms  are 
observed  in  purulent  nephritis  as  in  acute  parenchymatous 
nephritis,  except  that  in  those  cases  in  which  there  is 
absorption  of  quantities  of  pus,  when  there  is  evidence 
of  pyemia. 

Treatment. — Symptomatic  treatment  may  be  of 
value.  The  cause  should  be  removed,  and  the  patient 
given  sparingly  of  easilj^  digested  food. 

Chronic  Nephritis 

Chronic  nephritis  is  a  common  condition  in  swine. 
It  is  not  an  important  disease  from  the  viewpoint  of  the 
practitioner,  but  it  is  of  some  economic  importance  to 
the  packer  as  many  kidneys  are  found  to  be  affected. 
Chronic  nephritis  represents  a  group  of  pathologic  con- 
ditions— at  least,  there  is  a  variety  of  different  types  of 
lesions  observed.  One  type  of  chronic  nephritis  has  been 
studied  and  named  "chronic  non-indurative  nephritis," 
but  from  the  general  lesions  in  these  kidneys  it  seems 
probable  that  the  condition  is  confined  to  the  parenchyma 
and  should  be  called  "chronic  parenchymatous  neph- 
ritis." 

Chronic  Interstitial  Nephritis 

Typical  chronic  interstitial  nephritis  is  characterized 
by  the  proliferation  of  fibrous  tissue  which  may  or  may 
not  cicatrize.  This  condition  includes  white-spotted 
kidneys,  some  large  white  kidneys,  grauular  kidneys, 
sclerotic  atrophied  kidneys,  and  all  variations  of  the 
foregoing. 

Etiology. — Chronic  nephritis,  especially  the  type 
involving  only  the  supporting  framework,  is  caused 
primarily  by  relatively  mild  irritants  acting  over  a  long 
period  of  time.     These  cases  have  not  been  recognized 


THE  URO-GENITAL  SYSTEM  107 

clinically,  but  by  tracing  the  swine  that  show  the  lesions 
w^hen  slaughtered  it  is  usually  found  that  the  feed  of  the 
animals  has  been  at  fault.  In  some  cases  parasites  and 
calculi  are  responsible  for  the  condition. 

Lesions. — Chronic  parenchymatous  nephritic  kidneys 
are  enlarged.  The  capsule  is  not  easily  removed,  and 
when  pealed  off  small  fragments  of  kidney  tissue  remain 
attached  to  it .  The  kidney  is  mottled,  due  to  hemorrhages 
and  infarction,  and  there  is  no  definite  line  of  demarca- 
tion between  the  medulla  and  cortex.  Microscopically 
the  parenchymatous  cells  are  found  enlarged  and  cloudy, 
but  tube  casts  are  rarely  observed. 

Chronic  interstitial  nephritis  is  characterized  by 
fibrous  proliferation.  The  newly  formed  fibrous  tissue 
may  or  may  not  cicatrize.  The  gross  appearance  of  the 
kidney  varies  according  to  the  amount  and  disposition  of 
fibrous  tissue.  If  the  condition  is  localized  according 
to  the  distribution  of  small  arteries  the  fibrous  tissue  will 
occur  in  foci,  and  spotted  kidney  is  the  result,  the  white 
spots  being  masses  of  fibrous  tissue.  If  this  fibrous 
tissue  is  uniformly  deposited  throughout  the  kidney  and 
does  not  cicatrize,  the  kidney  is  enlarged,  dense,  and 
hard — one  of  the  types  of  the  large  white  kidney.  Granular 
kidneys  are  the  result  of  the  proliferation,  and  later 
cicatrization,  of  fibrous  tissue  in  and  around  the  glomeruli 
or  tubules.  Granular  kidneys  have  rough,  small  pro- 
jections thickly  studded  over  the  surface;  such  kidneys 
are  usually  of  a  red  color.  The  extensive  proliferation 
and  cicatrization  of  fibrous  tissue  in  all  the  cortical 
substance,  when  associated  with  a  thickening  of  the 
capsule,  produces  the  small,  hard,  or  sclerotic  kidney. 
Microscopically  excessive  quantities  of  fibrous  tissue  are 
found,  and  the  parenchymatous  tissue  is  diminished,  due 
to  pressure  atrophy.  Sometimes  there  may  be  large 
areas  of  fibrous  tissue  in  which  no  parenchymatous  tissue 
appears  or  only  remnants  of  tubules  or  glomeruli. 

Symptoms. — Records  of  the  clinical  evidence  of 
chronic  interstitial  nephritis  in  swine  are  wanting.    Swine 


108  SWINE  DISEASES 

with  extensive  kidney  lesions  are  usually  in  fair  condition 
when  they  are  observed  at  the  time  of  slaughter. 

Treatment. — The  application  of  therapeutic  agents 
for  the  relief  of  chronic  interstitial  nephritis  in  swine  has 
not  been  practiced.  Should  such  a  case  be  diagnosed, 
the  removal  of  the  cause  and  the  provision  of  good 
quarters  and  wholesome  food  would  probably  be  suf- 
ficient until  the  animal  was  in  condition  for  slaughter. 

Pyelonephritis 

Pyelonephritis  is  an  inflammation  of  the  pelvis  of  the 
kidney,  a  condition  that  has  been  observed  in  swine  but 
is  rare. 

Etiology. — Calculi  and  parasites  are  frequently  pre- 
disposing factors  in  this  disease.  Primarily,  the  disease 
is  the  result  of  infection.  Pyogenic  bacteria  may  cause 
the  condition,  but  more  frequently  it  is  caused  by  a 
pleomorphic  organism  that  has  been  named  corynebacillus 
renalis. 

Lesions. — The  pelvis  of  the  kidney  is  dilated  with  a 
thick,  brownish,  purulent  fluid  and  tissue  shreds.  The 
mucosa  of  the  renal  pelvis  is  thick  and  contains  hemor- 
rhagic spots.  The  kidney  may  contain  purulent  centers 
or  it  may  be  converted  into  a  purulent  mass. 

Symptoms. — Frequent  urination  is  a  symptom  of 
this  disease,  the  urine  voided  being  cloudy.  Loin  sensi- 
tiveness and  inappetence  are  also  observed  in  these 
cases. 

Treatment. — Thus  far  no  treatment  has  been  found 
that  is  of  any  value. 

Albuminuria 

Albuminuria  is  a  condition  in  which  there  is  elimination 
of  albumin  in  the  urine. 

Urinalysis  is  now  in  its  infancy  in  veterinary  medicine. 
Considerable  time  and  energy  have  been  devoted  to  the 
study  of  urine  from  some  animals,  particularly  the  horse, 
but  little  attention  has  been  given  to  systematic  urinalysis 
of  swine. 


THE  URO-GENITAL  SYSTEM  109 

Urine  has  been  collected  from  the  bladder  of  the 
carcasses  of  swine  that  have  been  slaughtered,  and 
analyzed.  It  is  possible  that  there  may  be  some  modi- 
fication of  the  urine  of  slaughtered  animals,  but  it  is 
doubtful  if  the  changes  are  of  much  significance. 

Albuminuria  has  been  found  to  exist  in  swine  showing 
a  high  temperature,  particularly  cases  that  have  been 
affected  with  cholera.  The  urine  has  also  been  found  to 
contain  varying  quantities  of  albumin  in  which  there  was 
an  acute  nephritis.  Pneumonic  cases  also  evidenced 
albumin  in  the  urine. 

The  exact  cause  of  albuminuria  is  still  being  debated. 
The  condition  in  swine,  as  well  as  in  other  animals, 
occurs  in  those  cases  where  the  renal  epithelium  is  dam- 
aged either  by  degeneration  or  inflammation,  although  it 
may  occur  in  the  absence  of  damaged  epithelium.  Some 
veterinarians  are  maintaining  that  albuminuria  is  caused 
by  acid  intoxication. 

At  this  time,  with  our  present  knowledge,  albuminuria, 
at  least  in  swine,  must  be  thought  of  as  secondary  to  some 
other  conditions.  Albuminuria  in  swine  has  not  been 
studied  clinically,  therefore,  symptoms  of  the  condition 
cannot  be  recorded.  It  is  an  important  condition 
because  albuminous  substances  that  should  be  conserved 
are  eliminated  from  the  body  in  the  urine.  Disturbances 
of  nutrition  follow,  and  the  primary  and  associated  con- 
ditions produce  emaciation  and  marasmus.  Albuminuria 
usually  terminates  fatally. 

Uremia 

Uremia  is  a  condition  characterized  by  the  presence 
in  the  blood  of  a  greater  or  less  amount  of  the  solid 
constituents  of  urine.  This  condition  has  not  been 
identified  clinically  in  swine,  but  the  nature  of  the  lesions 
observed  in  some  kidneys  by  veterinary  inspectors  is 
sufficient  evidence  that  the  disease  exists  in  swine. 

Etiology. — The  primary  cause  of  uremia  is  obstructed 
outflow  of  urine,  which  may  be  the  result  of  disturbance 
in  the  kidneys,  ureter  bladder,  or  urethra.     Severing  or 


110  SWINE  DISEASES 

puncturing  the  ureters  during  operations,  as  in  cesarean 
section,  may  result  in  uremia. 

Lesions. — No  particular  gross  tissue  changes  are 
attributed  to  uremia.  The  lesions  found  are  those 
incidental  to  the  obstruction  of  the  outflow  of  urine,  as 
calculi,  tumors,  and  so  on. 

Symptoms. — Stupor,  vertigo,  emesis,  inappetence, 
diarrhea,  clonic  muscular  spasms,  and  convulsions  are 
the  principal  symptoms  of  uremia.  The  disease,  at 
least  in  the  acute  form,  is  usually  fatal.  Chronic  uremia 
is  associated  with  digestive  derangements. 

Treatmient.^ — Removal  of  the  cause  is  practically 
always  successful  unless  the  case  is  too  far  advanced. 
Therapeutic  treatment  is  of  no  value. 

Parasites 

The  cystic  form  of  the  Taenia  solium  of  man  has  been 
observed  in  the  kidney  of  swine,  but  is  not  of  common 
occurrence  in  that  location.  The  cystic  forms  of  the 
tsenic  echinococcus  also  occur  in  this  organ. 

The  Stephanurus  dentatum  is  sometimes  found  in 
the  kidney  structure,  although  it  more  commonly  occurs 
in  the  perirenal  fat. 

Tumors 

The  kidney  of  swine  is  affected  with  adenosarcoma. 
In  the  living  swine  the  presence  of  these  tumors  is  not 
suspected.  They  appear  as  irregular,  incapsulated 
masses,  usually  involving  only  one  kidney,  and  in  size 
vary  from  five  to  fifteen  pounds.  Although  they  have 
not  been  recognized  clinically,  their  structure  and  appear- 
ance evidence  rapid  growth.  They  have  their  origin  in 
the  kidney  substance  near  the  pelvis,  and  the  tumor 
tissue  produces  pressure  atrophy  of  the  renal  parenchyma. 
The  outline  of  the  tumor  is  irregular  and  frequently 
lobulated.  On  being  sectioned,  fibrous  bands  are  found 
extending  in  various  directions  and  dividing  the  tumor 
mass  into  lobes.  The  neoplastic  tissue  is  of  a  white  or 
dirty-white   color,  but  is  often  mottled,  due  to  hemor- 


THE  URO-GENITAL  SYSTEM 


111 


rhage;  there  may  also  l)e  grayish-yellow  centers  of  necrosis. 
Microscopically  these  tumors  are  composed  of  embryonic 
epithelium  and  connective  tissue,  the  epithelium  disposed 
as  irregular  tubules  or  remnants  of  tubules,  while  the 
connective  tissue  occurs  around  and  between  the  epi- 
thelia  tumor  cells.      Sometimes  larger  areas  of  embryonic 


'# 


I 

V 


,» 


^' 


Fig:.    4.— ADEXO-SAKCOMA    Ol'    THE    KIDXEY. 
A.  Normal  kidney  tissue.     B.  hemorrhagic  areas.     C.  pelvis.       D.  sar- 
comatus  tissue.      (This  kidney   \\as   seven   or   eight  times   as   large  as 
a  normal  kidney.) 

connective  tissue  cells  are  found  independent  of  epi- 
thelium, and  again  the  epithelium  may  occur  in  nests  in 
the  sarcomatous  tissue. 

The  time  for  growth  of  these  tumors  has  not  been 
determined,  but  they  are  most  frequently  found  in  swine 
less  than  two  years  of  age. 


112  SWINE  DISEASES 

Sarcomas  have  also  been  encountered  by  veterinary 
inspectors  in  the  kidney  of  swine.  They  are  usually 
metastatic,  although  one  case  of  a  primary,  large-spindle 
celled  sarcoma  has  been  recorded. 

URETERS 

Malformations 

Malformations  of  the  ureters  are  not  uncommon,  but 
the  malformations  that  are  observed  are  not  of  such  a 
nature  that  the  function  of  the  organs  is  interfered  with 
and  therefore  are  of  no  practical  importance. 

Renal  pelvic  calculi  may  become  lodged  in  the  ureters 
and  establish  inflammatory  disturbances,  and  also  obstruct 
the  lumen. 

The  ureters  are  subject  to  injuries  in  spaying  and  other 
abdominal  operations. 

BLADDER 

Malformations 

Malformations  of  the  bladder  are  not  common.  A 
few  cases  of  double  bladder  have  been  recorded,  or  the 
bladder  may  be  very  small,  such  animals  urinating 
frequently.  Vestiges  of  the  urachus  may  be  retained, 
and  these  may  become  cystic. 

Hematuria 

Hemorrhages  into  the  bladder  sometimes  occur  in 
swine.  They  are  caused  by  injuries  which  may  be 
inflicted  by  calculi  and  from  diseases  of  the  mucosa. 
They  may  also  be  caused  by  drugs,  such  as  cantharides 
and  turpentine,  obtained  accidentally  in  large  quantities. 
This  condition  is  frequently  associated  with  such  diseases 
as  hog  cholera. 

Lesions. — The  primary  lesions  observed  depend 
vipon  the  cause  of  hematuria.  There  may  be  cystic 
calculi,  injuries  of  various  kinds,  infection,  and  lesions 
elsewhere  in  the  body.     The  extravasted  blood  will  be 


THE  UROGENITAL  SYSTEM  113 

accumulated  in  the  bladder  and  may  or  may  not  be 
coagulated,  and  the  entire  bladder  content  will  be  colored 
red  with  hemaglobin  liberated  from  the  disintegrated  red 
blood  cells. 

Symptoms. — Hematuria  is  evidenced  by  bloody 
urine  in  which  the  entire  urine  is  uniformly  red.  It  is 
distinguished  from  renal  hemorrhage  by  the  absence  of 
tube  casts,  and  from  urethral  hemorrhages  by  the  fact 
that  in  urethral  hemorrhage  only  the  first  urine  voided  is 
red. 

Treatment. — The  exact  cause  should  be  identified 
and  removed.     Urinary  sedatives  may  also  be  of  value. 

Dilatation 

Cystic  dilatation  is  sometimes  occasioned  by  urethral 
obstruction  or  spasms  of  the  muscles  in  the  neck  of  the 
bladder.  The  urine  continues  to  be  produced  in  the 
kidney  and  accumulates  in  the  bladder  until  its  capacity 
may  be  far  in  excess  of  the  normal. 

Lesions. — The  characteristic  lesion  of  dilatation  con- 
sists of  distention  of  the  bladder  and  attenuation  of  its 
walls.  In  fatal  cases  the  bladder  ruptures  and  urine  and 
uriniferous  odor  are  detected  when  the  abdomen  is  opened, 
and  the  rent  in  the  bladder  wall  will  also  be  evident. 

Symptoms. — Distress,  anuria,  frequent  attempts  at 
urination,  and  possibly  some  enlargement  of  the  abdomen 
characterize  distended  bladder.  In  distention  succeeded 
by  rupture  the  foregoing  symptoms  would  be  succeeded 
by  stupor,  vertigo,  emesis,  inappetence,  diarrhea,  clonic 
muscular  spasms,  convulsions,  and  death. 

Treatment. — Treatment  is  available  only  during 
distention,  and  effort  should  be  directed  principally  to 
removing  the  cause.  If  it  is  a  urethral  obstruction  in  the 
male  and  the  obstruction  is  below  the  ischiatic  arch  an" 
artificial  opening  may  be  made  into  the  urethra  where  it 
passes  over  the  ischiatic  arch,  giving  temporary  relief, 
and  if  the  obstruction  cannot  then  be  removed  the  tem- 
porary opening  in  the  urethra  may  be  made  permanent. 
In  valuable  animals  obstructive  calculi  may  be  removed 


114  SWINE  DISEASES 

from  the  bladder  l)y  surgical  procedure  and  the  condition 
thus  corrected.  Tumors  and  abscesses  that  affect 
urethral  obstruction  may  be  removed  and  permit  of  the 
ready  outflow  of  urine  through  the  urethra. 

Calculi 

Cystic  calculi  are  of  common  occurrence  in  swine. 
There  may  be  a  single  calculus  or  there  may  be  myriads 
of  them.  In  size  they  vary  from  mere  grains  of  sand  to 
masses  as  large  as  English  walnuts.  In  shape  they  may 
be  spherical,  ovoid,  or  all  kinds  of  irregular  surfaces  and 
outlines  may  be  presented.  Some  have  been  observed 
that  were  practically  the  shape  of  jack  straws.  When 
several  occur  together  they  may  be  faceted.  As  a  rule 
they  are  of  a  dirty-white  color,  though  they  may  be  of 
any  color.  They  are  usually  composed  of  magnesium 
and  calcium  phosphates  and  carbonates. 

Etiology. — Retention  and  fermentation  of  urine  in 
the  bladder  favor  calculous  formation.  Retention  and 
urine  fermentation  also  favor  catarrhal  inflammation, 
which  is  associated  with  epithelial  desquamation,  and  this 
serves  as  a  nucleus  for  the  calculous  deposits. 

Lesions. — The  presence  of  calculi  is  the  principal 
thing  to  be  sought  for,  and  they  are  not  difficult  to 
identify.  There  is  also  more  or  less  evidence  of  catarrhal 
cystitis,  and  there  may  be  retention  of  urine. 

Symptoms. — Evidence  of  catarrhal  cystitis — that  is, 
frequent  voiding  of  relatively  small  quantities  of  urine — 
characterizes  most  cases  of  cystic  calculi.  The  urine  in 
these  cases  is  frequently  acrid  and  may  produce  dis- 
turbances in  and  around  the  prepuce  of  the  male  and  in 
the  perineal  region  of  the  female.  Should  the  calculi 
produce  obstruction  to  the  outflow  of  urine  there  will  be 
'symptoms  of  cystic  distention. 

Treatment. — Solvents  for  cystic  calculi  are  not 
wholly  successful.  If  the  calculi  are  causing  such  dis- 
turbance that  marked  symptoms  are  evident,  operative 
procedure  is  indicated,  providing  the  value  of  the  animal 
is  sufficient  to  justify  it. 


THE  URO-GENITAL  SYSTEM  115 

Cystitis 

Inflammation  of  the  bladder  may  be  catarrhal  or 
purulent.  Neither  type  has  been  extensively  investi- 
gated by  the  clinician,  therefore  the  present  knowledge 
concerning  them  has  been  obtained  by  veterinarians  at 
abattoirs. 

Catarrhal   Cystitis 

Catarrhal  cystitis  is  not  uncommon.  In  many 
instances  the  condition  is  associated  with  cystic  calculi, 
but  it  may  also  be  caused  by  infection.  Occasionally 
several  cases  of  catarrhal  cystitis  may  occur  simultaneously 
or  successively  in  the  same  herd,  and  on  obtaining  the 
history  it  is  found  that  the  affected  swine  have  been  fed 
food  stuff  containing  some  urinary  irritant  or  they  have 
obtained  quantities  of  turpentine  or  cantharides.  Reten- 
tion and  fermentation  of  the  urine  predisposes  to  inflam- 
mation of  the  cystic  mucosa  because  of  the  liberation  of 
ammonia. 

Lesions. — Catarrhal  cystitis  is  characterized  by  the 
following  sequential  lesions  of  the  mucosa:  hyperemia, 
tumefaction,  and  coating  of  the  surface  with  tenacious 
mucus,  desquamated  epithelia,  and  pus  cells.  Later 
there  is  desquamation  of  the  surface  epithelium,  leaving 
a  denuded  granulating  surface. 

Symptoms. — Frequent  attempts  at  urination  in 
which  small  quantities  of  a  turbid  urine  is  eliminated 
are  symptoms  of  catarrhal  cystitis.  There  may  be  a 
straddling  gait. 

Treatment. — Remove  the  cause.  The  bladder  in 
females  may  be  cleansed  by  a  weak  solution  of  corrosive 
sublimate  or  creolin,  and  urinarj'  sedatives  should  be 
administered.  Internal  treatment  is  practicaUy  all  that 
can  be  given  in  male  animals  affected  with  cystitis. 

Purulent  Cystitis 

Purulent  cystitis  is  an  inflammation  of  the  urinary 
bladder  accompanied  by  the  formation  of  pus.  This 
condition  is  not  so  common  in  swine  as  catarrhal  cystitis. 


116  SWINE  DISEASES 

Predisposing  causes  mentioned  in  catarrhal  cystitis  are 
also  operative  in  purulent  cystitis.  The  exciting  cause  is 
most  frequently  the  Bacillus  coli  communis,  although 
any  of  the  pyogenic  cocci  may  produce  it,  or  even  the 
Bacillus  pyocyaneus  being  responsible  for  an  occasional 
case  of  cystitis. 

Lesions. — Hyperemia,  tumefaction  of  the  mucosa, 
accumulation  of  tenacious  mucus  upon  the  mucosa,  and 
the  production  of  pus  in  quantities  characterize  purulent 
cystitis.  The  surface  mucosa  is  eroded  and  becomes  a 
granulating  surface. 

Symptoms. — Frequent  urination  and  the  voiding  of 
small  quantities  of  urine  admixed  with  pus  typifies 
purulent  cystitis. 

Treatment. — Remove  the  cause,  and  cleanse  the 
bladder  of  females  with  weak  antiseptics.  The  males 
should  be  treated  by  internal  medication,  with  urinary 
antiseptics  and  sedatives. 

Tumors 

Very  few  cases  of  the  occurrence  of  tumors  have  been 
observed  in  the  bladder  of  swine.  Papillomata  have 
been  reported  in  a  few  cases. 

URETHRA 

The  urethra  may  be  imperforate,  particularly  in  the 
male.  Such  cases  are  rarely  observed,  and  those  affected 
die  soon  after  birth.  The  condition  is  easily  remedied, 
providing  the  imperforation  is  near  the  outlet,  by  making 
a  crucial  incision  or  by  puncture  with  a  small  trocar. 

Injury  of  the  urethra  in  males  may  be  inflicted  by 
contact  with  barbed  wire  or  other  sharp  objects,  and  the 
female  urethra  may  be  injured  by  forceps  used  during 
parturition.  These  injuries  are  not  serious,  though 
occasionally  they  may  result  in  permanent  fistulas. 

Stricture 

Stricture  of  the  urethra  may  follow  injuries  or  inflam- 
mation.    In    male    swine    catheterization    is    not    prac- 


THE  URO-GENITAL  SYSTEM  117 

ticable,  and  it  is  not  an  easy  matter  to  locate  a  stricture 
or  other  obstruction  in  their  urethrae. 

Urethritis 

Urethritis  occurs  in  swine.  It  is  most  frequently  a 
sequel  of  cystitis,  although  it  may  occur  as  a  primary 
condition.  It  is  probably  more  common  in  males  than 
in  females,  and  is  evidenced  by  painful  urination.  Treat- 
ment consists  in  giving  urinary  sedatives  and  inducing 
the  animals  to  drink  large  quantities  of  clean,  wholesome 
water  in  order  that  the  urine  may  be  diluted. 

MALE   GENERATIVE  ORGANS 

PROSTATE  GLAND 

The  prostate  gland  is  located  beneath  the  vesiculai 
seminales  and  embraces  the  neck  of  the  bladder.  This 
gland  is  not  well  developed  except  in  boars.  It  is  occa- 
sionally enlarged,  due  to  infection  with  tubercle  bacilli, 
colon  bacilli,  or  pyogenic  cocci.  There  may  be  abscess 
formation  or  fibrous  proliferation  in  the  prostate.  En- 
larged prostates  partially  obstruct  the  urethra  by  pressure, 
thus  making  urination  difficult. 

BULBO-URETHRAL  OR  COWPER'S  GLANDS 

These  are  large  glandular  structures  located  on  either 
side  of  the  posterior  portion  of  the  pelvic  urethra.  They 
are  less  developed  in  the  castrated  animal,  particularly 
if  the  operation  be  done  in  early  life.  They  are  also 
subject  to  infection  and  enlargement  which  produces 
pressure  obstruction  upon  the  urethra. 

TESTICLES 

Malformations  of  the  male  sexual  glands  are  not 
uncommon,  one  or  both  testicles  sometimes  being  abnor- 
mally small.  Cryptorchidy  is  of  common  occurrence  in 
swine.  De  Wolf  inspected  4,671  male  swine  and  found 
twenty-eight  single  and  seven  double  cryptorchids. 
Nearly  five  per  cent  of  the  male  progeny  of  one  of  IVIis- 


118  SWINE  DISEASES 

souri's  most  famous  boars,  Chief  Tecumseh  II,  were 
cryptorchids.  Liberty  Chief  and  Chief  I  Know,  two 
boars  sired  by  Chief  Tecumseh  II,  were  noted  breeders, 
and  from  three  to  five  per  cent  of  their  get  were  cryp- 
torchids. Chief  Perfection  II,  sired  by  Chief  Tecumseh 
II,  was  the  sire  of  Chief  Cherokee  Perfection,  that  in 
turn  sired  about  three  per  cent  of  cryptorchids.  Cryp- 
torchidism diminishes  the  vahie  of  a  pig  because  of  the 
greater  castration  risk. 

Because  of  their  location,  tlie  testicles  of  a  boar  are 
subject  to  injuries  of  various  kinds.  Some  instances 
have  been  observed  in  which  it  was  necessary  to  castrate 
valuable  boars  that  had  their  testicles  so  lacerated  that 
recovery  of  the  function  of  them  was  not  possible.  In- 
juries may  be  inflicted  by  dogs,  sharp-cutting  objects,  or 
by  crushing,  as  a  result  of  cattle  or  horses  treading  upon 
the  glands. 

Orchitis  and  Epididymitis 

Inflammation  of  the  testicle  has  been  observed,  but 
is  not  of  common  occurrence  in  swine.  Orchitis  and 
epididymitis  are  not  easily  differentiated.  They  are  most 
frequently  the  result  of  mechanical  injury,  although 
they  may  result  from  infection.  Tuberculous  orchitis  is 
not  uncommon  in  swine. 

Lesions. — The  affected  testicles  or  epididymi  are  en- 
larged and  hyperemic.  The  secreting  structure  have  a 
parboiled  appearance.  Suppurative  orchitis  is  charac- 
terized by  the  formation  of  abscesses,  or  it  may  assume  a 
diffuse  form  of  suppuration  in  which  pus  infiltrates  the 
tubular  and  intertubular  tissue. 

Microscopically,  the  arterioles  and  capillaries  are 
gorged  with  blood,  and  there  is  exudation  into  the 
seminiferous  tubules  and  intertubular  spaces  of  leukocytes 
and  plasma.  The  spermatogenic  cells  are  cloudy  and 
may  show  disintegration.  The  spermatozoa  are  more  or 
less  disintegrated  and  inactive. 

Symptoms. — Enlarged,  sensitive  testicles  are  the 
chief  symptoms  by  means  of  which  orchitis  or  epididy- 


THE  UROGENITAL  SYSTEM  119 

mitis    is    identified.     There    may    be    abnormal    sexual 
excitement. 

Treatment. — Unless  the  animal  is  very  valuable  for 
breeding  purposes,  castration  should  be  resorted  to; 
otherwise,  remove  the  cause  and  apply  hot  compresses, 
or  alternating  hot  and  cold  compresses,  upon  the  affected 
glands.  Place  the  patient  in  comfortable  quarters  and 
where  there  will  be  no  occasion  for  sexual  excitement. 
Tumors 

Testicular  tumors  are  not  common  but  appear  as 
frequently  in  swine  as  in  other  animals.  Both  dermoid 
and  dentigerous  cysts  have  been  encountered  in  the 
testicle,  and  while  these  are  not  destructive  to  life,  they 
damage  the  animal  for  breeding  purposes.  Sarcomas  and 
endotheliomas  occasionally  occur  in  the  testicle,  and  are 
usually  primary.  They  are  malignant  tumors,  however, 
and  swine  with  enlarged  testicles  are  usually  castrated. 
Fortunately,  the  operation  is  commonly  performed 
before  the  tumors  ha^'e  metastasized,  and  thus  the  lives 
of  the  swine  are  not  sacrificed. 

SEQUELS  TO  CASTRATION 

Castration  of  male  swine  is  the  usual  practice.  The 
proper  age  that  pigs  should  attain  before  being  castrated 
depends  somewhat  upon  climatic  conditions.  Castration 
as  a  rule  should  be  done  about  weaning  time,  for  if  there 
should  be  any  fatalities  from  the  operation  the  loss  will 
be  less  then  than  later.  It  should  not  be  delayed  until 
the  swnne  are  matured,  or  the  meat  will  have  a  strong 
flavor.  Some  have  made  a  practice  of  castrating  imme- 
diately after  the  pigs  are  farrowed — usually  with  good 
success,  as  the  operation  does  not  appear  to  hinder 
development . 

Castration  of  swine  is  usually  practiced  by  the  lay- 
man and  only  occasionally  do  bad  results  ensue. 
Hemorrhage 

Rarely  does  a  pig  bleed  to  death  as  a  secjuel  to  cas- 
tration, but  this  does  occur  occasionally.  Old  boars  are 
prone  to  bleed  freely  unless  proper  precaution  is  taken. 


120  SWINE  DISEASES 

Infection 

The  castration  wounds  are  subject  to  a  variety  of 
infection  because  of  their  location  and  the  nature  and 
habit  of  swine.  Various  pyogenic  bacteria  gain  entrance 
into  the  castration  wound,  and  should  the  incisions  be 
small  and  the  wound  margins  closed  by  the  inflamma- 
tory swelling  an  abscess  may  develop,  the  size  of  which 
will  depend  upon  the  tissue  resistance.  Scrotal  abscesses 
in  castration  wounds  are  not  serious  if  properly  opened, 
drained,  and  cared  for,  but  if  the  pus  is  allowed  to  accumu- 
late it  may  infiltrate  the  surrounding  tissues  or,  more 
probably,  pass  along  the  vas  deferens,  and  ultimately 
enter  the  pelvic  cavity  and  establish  peritonitis. 

The  colon  bacillus  may  also  infect  castration  wounds 
and  produce  either  suppurative  or  septic  inflammation. 
In  a  few  instances  several  pigs  have  been  observed 
affected  with  septic  disturbances  resulting  from  colon 
infection  in  castration  wounds.  The  lesions  observed  in 
septic  infection  consist  of  gaseous  tumefactions  containing 
inflammatory  products.  These  cases  usually  terminate 
fatally,  unless  treatment  is  begun  early.  The  treatment 
consists  of  opening  the  castration  wounds,  removing 
the  necrotic  tissue  with  a  curette,  and  freely  applying 
efficient  germicidal  agents. 

The  Bacillus  necrophorous  occasionally  gains  entrance 
to  the  castration  wounds,  but  the  successful  infection  by 
these  germs  is  usually  in  the  later  stages  of  the  healing 
process.  The  Bacillus  necrophorous  is  anaerobic  and 
probably  is  continuously  eliminated  in  the  feces.  The 
lesions  produced  by  this  organism  consist  of  a  slow-going 
necrosis,  the  necrotic  foci  being  surrounded  by  an  inflam- 
matory zone.  A  peculiar,  offensive  odor  emanates  from 
the  lesions.  The  necrotic  areas  may  later  show  evidence 
of  separation  from  the  surrounding  tissue,  and  ultimately 
the  lesion  may  become  desiccated  and  slough,  leaving  a 
dark-colored  surface  upon  which  tissue  fragments  and 
pus  may  accumulate.  These  cases  may  prove  fatal, 
but  more  frequently  the  animals  linger  for  some  time, 
the  surrounding  tissue  becoming  tumefied  due  to  the 


THE  URO-GENITAL  SYSTEM 


121 


proliferation  of  fibrous  tissue.  In  such  cases  there  is  a 
variable  sized  opening  or  unhealed  surface.  If  the 
large  fibrous  mass  is  removed  and  incised  it  will  be  found 
to  contain  necrotic  centers  composed  of  fluid,  semi- 
fluid, or  caseous  material.  These  centers  are  surrounded 
by  fibrous  tissue,  the  entire  mass  being  made  up  of  layer 
upon  layer  of  fibrous  lamellae.  The  end  of  the  vas 
deferens  will  be  found  involved  in  the  mass,  to  which  it 
usually  adheres  firmly,  or  to  the  external  surface  of  the 
wound,  by  dense  fibrous  tissue.     This  condition  in  the 


Fig.   5.— ACTINOMYCOSIS. 


beginning  may  be  identified  by  the  tumefaction  and 
particularly  by  the  bad  odor  of  the  discharge.  Later 
the  large  lesion  is  observed  with  the  characteristic  putrid 
discharge  from  the  open  wound. 

Treatment. — In  the  early  stages  the  condition  may 
be  relieved  by  the  energetic  application  of  disinfectants, 
and  if  necrosis  is  present  the  excision  or  curettment  of  the 
necrotic  centers.  After  the  dense  mass  of  fibrous  tissue 
has  formed,  only  the  careful  removal  of  the  entire  mass 
by  operation  is  successful;  and  in  this  the  greatest  care 


122 


SWINE  DISEASES 


must  be  exercised  or  the  animal  will  bleed  to  death. 
The  operative  wound  should  receive  the  proper  after- 
treatment. 

Botryomyces 

The  Botryomyces  ascoformans  also  infects  castration 
wounds  in  swine.  This  condition  is  very  common  in 
certain  localities  at  some  seasons.  It  is  of  a  chronic, 
insidious  nature.  The  castration  wounds  may  heal  and 
be  apparently  normal,  the  first  indication  of  the  condition 


Fiff.   6.— SCIRRHOUS    CORD    DUK   TO    BOTRYOMYCOTIC 
INFKrxiOX. 

being  a  slight  enlargement  of  the  scrotum.  The  enlarge- 
ment persists  and  gradually  increases  in  size  until  it  is 
quite  large;  in  some  instances  these  masses  may  attain 
the  size  of  a  football.  On  examination  of  the  affected 
pig  a  rather  dense  mass  can  be  outlined,  apparently 
adhered  to  the  substructures  but  not  attached  to  the 
skin  unless  the  wound  has  failed  to  heal.  These  masses 
are  found  to  be  encapsulated  with  dense  fibrous  con- 
nective tissues.  Oji  sectioning  the  growth,  many  centers 
are   found    from    one-half    to    two    inches    in    diameter. 


THE  UROGENITAL  SYSTEM  123 

These  centers  contain  pus  which  may  be  caseous,  and 
the  various  centers  communicate  by  means  of  fistulous 
tracts. 

Treatment  consists  of  ablation  of  the  entire  mass, 
which  is  ordinarily'  not  difficult  as  the  lesion  is  sub- 
cutaneous and  is  definitely  circumscribed. 

Actinomycosis 

Actinomycosis  may  affect  the  scrotum  of  castrated 
swine,  but  is  not  common. 

Parasites 

Infestation  of  the  castration  wounds  with  screw- 
worms  (larvae  of  the  Campsomyia  macellaria)  are  very 
common  in  the  southern  part  of  the  United  States. 
These  larvae  burrow  into  the  tissues,  thus  mechanically 
injuring  them  and  providing  an  avenue  of  entrance  for 
various  bacteria. 

Lesions. — The  principal  lesions  consist  of  an  active, 
acute  inflammation  mth  or  without  the-  production  of 
pus.  The  surrounding  tissues  are  tumefied,  hyperemic, 
hemorrhagic,  and  contain  the  larvae.  The  extensive 
tumefaction  developing  within  one  or  two  days  after 
castration  is  the  most  evident  symptom.  On  a  close 
inspection,  larvae  may  be  observed  near  or  upon  the 
surface,  and  by  manipulation  of  the  lesion  larvae  may 
be  forced  out  upon  the  surface.  In  cases  of  screw-worm 
infestation  there  is  a  constant  sero-sanguinous  discharge 
that  by  attracting  the  female  fly  favors  repeated  rein- 
festation. 

Treatment. — All  that  can  be  done  in  cases  of  screw- 
worm  infestation  is  to  support  the  strength  and  minister 
to  the  comfort  of  the  animal  and  prevent  a  further 
infestation  from  the  deposition  of  more  eggs  or  larvae 
upon  the  wound  and  patiently  wait  for  the  investing 
larvae  to  reach  the  stage  of  development  when  they 
voluntarily  leave  the  wound  to  pupate  in  the  ground. 
This  occurs  in  three  to  five  days. 

The  application  of -chloroform,  naphthalene  or  other 
chemicals   to   the   wound   is   worse   than   useless.     Such 


124  SWINE  DISEASES 

measures  not  only  fail  to  effect  the  removal  of  more  than 
a  small  percentage  of  the  larvae,  but  they  also  irritate 
the  highly  sensitive  tissues  and  greatly  aggravate  the 
condition. 

None  of  the  ordinary  fly-repellants  has  any  deterrent 
effect  upon  the  female  of  the  screw-worm  fly  in  the 
presence  of  fresh  blood,  either  in  recent  wounds  or  in  the 
discharge  from  screw-worm  infested  wounds.  However, 
a  mixture  composed  of  turpentine  one  dram,  phenol  one 
dram  and  cottonseed  oil  four  ounces  is  an  effective  re- 
pellent for  this  fly,  and  where  there  is  a  probability  of 
screw-worm  infestation  it  should  be  applied  to  fresh 
wounds  and  to  infested  wounds  as  long  as  the  screw- 
worm  larvae  are  present  and  the  sanguinous  discharge 
continues.     One  application  daily  is  sufficient. 

Scrotal  Hernia 

This  form  of  hernia  occurs  in  the  male.  It  consists 
of  a  protrusion  of  omentum  or  intestine  through  the 
inguinal  canal  and  into  the  scrotal  sac. 

Scrotal  hernia  may  be  limited  or  extensive;  in  some 
instances  the  scrotum  may  be  as  large  as  a  gallon  jug. 
Raising  the  hind  parts  of  the  pig  usually  permits  of  a 
portion  of  the  protruded  structure  passing  back  into  the 
abdomen,  and  thus  reduces  the  hernia. 

This  condition  is  relieved  only  by  operation  in  which 
castration  is  required  if  it  has  not  been  done  previously. 
The  covered  operation  is  performed,  and  the  vaginal 
tunic  is  supported  by  sutures. 

PENIS 

Malformations  of  the  penis  are  rare.  One  case  has 
been  observed  of  a  double  penis,  the  organ  being  double 
from  the  ischial  arch.  Each  penis  contained  a  normal 
urethra,  the  two  uniting  at  the  arch  and  continuing  to 
the  bladder  as  a  single  urethra. 

Injury  to  the  penis  of  barrows  is  rare,  although 
incised  wounds  may  sever  this '  organ.  The  penis  of 
boars  may  be  injured  by  permitting  breeding  in  quarters 


THE  URO-GENITAL  SYSTEM  125 

containing  machinery  or  other  places  where  injuries  of 
various  kinds  may  be  inflicted. 

Preputial  concrements  or  calculi  sometimes  occur  in 
swine.  They  occasion  difficulty  in  urination  or  even 
retention  of  urine  and  sometimes  the  urine  accumulates 
in  the  sheath  in  considerable  quantities.  The  accretions 
are  easily  detected  by  an  examination  and  are  not  difficult 
to  remove. 

The  lining  of  the  prepuce  may  be  infested  with  screw- 
worms,  which  will  occasion  considerable  swelling  and 
distress  to  the  animal.  For  the  treatment  see  page  123. 
Preputial  inflammation  due  to  irritation  from  urine  and 
infection  sometimes  requires  care  by  cleansing  and  anti- 
septics, 

FEMALE  REPRODUCTIVE  ORGANS 

OVARY 

Malformations 

Malformations  of  the  ovary  are  much  more  common 
than  is  generally  suspected.  The  most  frequent  anomalies 
consist  of  changed  position  which  ordinarily  does  not 
appear  to  interfere  with  the  normal  functioning  of  the 
organs.  There  may  be  two  ovaries  on  one  side  and  one 
on  the  other,  or  there  may  be  two  ovaries  on  each  side. 
Either  ovary  may  be  exceptionally  large  or  small,  the 
other  being  normal  in  size. 

The  ovaries  may  be  injured,  but  this  is  rather  the 
exception,  ownng  to  the  thick  body  wall  which  serves  as  a 
protection. 

Hemorrhage 

Hemorrhage  of  the  ovary  may  occur  at  the  time  of 
estrum,  and  is  dependent  upon  the  lacerating  of  a  blood 
vessel  when  the  graafian  follicle  ruptures.  These  hem- 
orrhages are  of  no  practical  or  economic  significance. 

Oophoritis 

This  condition  has  been  observed  in  sows,  but  princi- 
pally at  abattoirs  by  veterinary  inspectors.     It  is  usually 


126  SWINE  DISEASES 

secondary  to  metritis  or  salpingitis,  though  it  may  be 
metastatic  or  even  primary. 

Lesions. — Tlie  affected  ovary  is  enlarged,  and,  the 
surface  being  irregular,  nodular  projections  of  varying 
size  occur.  In  the  beginning  the  ovary  is  intensely 
red  and  cut  surfaces  bleed  freely.  The  nodules  repre- 
sent enlarged  graafian  follicles,  which  usually  contain  a 
gelatinous  substance  and  sometimes  blood.  Latent 
suppurative  centers  may  occur  and  may  or  may  not  be 
definitely  circumscribed  by  a  fibrous  capsule.  The  con- 
dition may  assume  a  chronic  form,  the  ovarian  structure 
becoming  dense  and  hard  due  to  the  proliferation  of 
fibrous  tissue. 

Symptoms. — The  principal  evidence  of  ovarian 
inflammation  is  persistent  sexual  desire,  and  is  manifested 
by  excitement,  frequent  urination,  and  the  search  for  a 
mate. 

Treatment. — Anodynes  may  be  used  to  quiet  the 
animal  temporarily,  and  the  blood  supply  may  be  diverted 
by  means  of  a  saline  purgative  or  atropine  in  full  physio- 
logic doses.  Therapeutic  agents  are  not  at  all  certain  in 
these  cases,  and  if  the  patient  is  not  especially  valuable  for 
breeding  purposes,  spaying  is  recommended. 

Cysts 

Ovarian  cysts  are  quite  common  in  sows.  They 
probably  have  their  origin  from  graafian  follicles  that 
have  failed  to  properly  mature.  One  or  both  ovaries 
may  be  affected.  The  cystic  ovary  may  be  uniformly 
enlarged  or  it  may  be  lobulated,  the  size  attained  being 
variable.  Reyer  reported  a  case  in  which  an  ovarian 
cyst  was  found  weighing  seven  pounds. 

Lesions. — The  affected  ovary  may  contain  either  a 
single  cyst  or  many  cysts.  The  cyst  may  be  ovoid, 
spherical,  or  lo])ulated.  In  those  cases  of  multiple  cysts 
the  cysts  sometimes  communicate  with  each  other  or 
are  multilocular.  The  cystic  content  may  be  a  thin, 
limpid  fluid,  jelly-like,  glue-like,  bloody,  or  even  caseous. 


THE  URO-GENITAL  SYSTEM  127 

Symptoms. — The  .syniptoms  presented  by  a  sow 
affected  with  cystic  ovaries  are  variable.  There  may  be 
indigestion  and  circnlatory  disturbances,  but  the  most 
common  symptom  is  persistence  of  the  estral  j^eriod,  the 
affected  animals  usuallj^  failing  to  conceive. 

Treatmient. — Oophorectomy  is  the  only  apparent 
relief  for  cystic  ovaries.  If  only  one  ovary  is  affected, 
the  sow  may  still  be  used  for  breeding  purposes. 

Dermoid  and  Dentigerous  Cysts 

Dermoids  and  dentigerous  cysts  occur  in  the  ovary, 
but  are  not  of  common  occurrence  in  swine. 
Tumors 

Endotheliomas  and  sarcomas  have  been  observed  in 
the  ovary  of  swine,  but  they  are  rare.  They  partake  of 
the  same  nature  as  do  these  tumors  occurring  elsewhere 
in  the  body. 

FALLOPIAN  TUBES 

Malformations  of  the  fallopian  tubes  are  not  common. 
Injuries  to  the  tubes  may  occur  during  the  operation  of 
spaying  or  cesarean  section. 

An  occasional  case  of  pyosalpinx  is  observed  in  the 
carcasses  of  swine  slaughtered  at  abattoirs.  This  con- 
dition is  uncommon,  and  apparently  of  little  clinical 
interest. 

UTERUS 

Malformations 

Malformations  of  the  uterus  are  not  significant 
because  the  majority  of  swine  are  fattened  for  market 
and  are  not  used  for  breeding  purposes.  An  occasional 
anomaly  is  observed,  such  as  a  rudimentary  uterus, 
double  uterus,  atresia  of  the  cervix,  and  so  on. 

Injuries 

Injuries  to  the  uterus  are  not  common  except  in 
those  animals  that  have  had  difficulty  in  parturition  and 
in  which  instruments  have  been  used.     In  many  instances 


128  SWINE  DISEASES 

injuries  produce  no  bad  after  effect,  but  occasionally  they 
provide  an  avenue  of  entrance  for  infection  of  the  peri- 
toneum and  may  result  in  fatal  peritonitis. 

Hemorrhage 

Uterine  hemorrhage  in  the  sow  is  not  of  the  same 
gravity  as  it  is  in  the  larger  animals;  however,  its  control 
is  more  difficult  in  the  sow  than  in  larger  animals  because 
of  the  small  size  of  the  uterus. 

Metritis 

Metritis  is  not  so  common  in  the  sow  as  it  is  in  the 
larger  animals,  or  even  in  the  sheep  and  goat.  This  is 
probably  because  of  the  fact  that  retention  of  the  pla- 
centa is  not  so  common  in  sows  as  in  almost  all  other 
animals.  The  usual  cause  of  metritis  is  infection,  which 
ordinarily  is  a  sequel  to  injuries,  retained  placenta,  or 
dead  fetuses.  The  sow  appears  to  possess  considerable 
resistance  to  uterine  infection,  for  cases  of  metritis  are 
relatively  rare,  and  as  further  evidence  of  their  resistance 
mummified  fetuses  are  of  common  occurrence  in  sows. 

Metritis  may  be  either  purulent  or  septic. 

Purulent  Metritis 

Purulent  metritis  is  characterized  by  hyperemia  and 
tumefaction  of  the  uterine  mucous  membrane.  Later 
there  is  desquamation  of  areas  of  the  mucous  membrane 
and  accumulation  of  quantities  of  pus  in  the  uterine 
cavity.  Should  the  cervix  become  closed,  there  may  be 
a  marked  distention  of  the  uterus  with  the  accumulated 
pus.  The  inflammation  may  extend  into  and  involve 
the  muscular  coat  of  the  uterus  or  even  the  serous  mem- 
brane. In  addition  to  the  inflammatory  lesions  there 
may  be  lacerations  and  various  other  injuries. 

Septic  Metritis 

Septic  metritis  is  characterized  by  intensive  inflam- 
mation involving  in  turn,  as  the  disease  progresses,  the 
mucosa,  muscularis,  and  serosa.     The  uterus  usually  con- 


THE  URO-GENITAL  SYSTEM  129 

tains  a  bloody,  putrid  fetus  or  fetuses,  as  septic  metritis  is 
most  freciuently  a  sequel  of  retention  and  ])utrefaction  of 
the  young. 

Prognosis  should  be  guarded,  as  the  disease  is 
usually  fatal. 

Symptoms. — Prostration  and  a  purulent  or  putrid 
discharge  from  the  vulva  are  the  primary  signs  of  septic 
metritis.  There  is  inappetence,  fever,  and  hyper- 
sensitiveness    of    pelvic    region. 

Treatment. — Irrigation  of  the  uterus  and  a  washing 
away  of  the  offending  material  is  essential,  but  is  attended 
with  some  difficulty  in  the  sow  owing  to  the  small  size  of 
the  genital  organs.  Hysterectomy  has  been  advised  but 
should  not  be  practiced  in  those  cases  showing  high 
temperature  and  prostration,  and  it  is  doubtful  if  it  will 
prove  successful  in  sufficient  number  of  cases  to  justify 
its  use. 

Tumors 

Various  tumors,  such  as  fibroma,  myxoma,  sarcoma, 
epithelioma,  and  carcinoma,  have  been  observed  in  the 
uterus.  The  various  tumors  partake  of  the  same  general 
nature  as  the  same  type  of  tumor  elsewhere  in  the  body. 
Should  an  antemortem  diagnosis  be  made,  and  the 
tumor  found  to  be  producing  considerable  injury,  hys- 
terectomy is  indicated. 

VAGINA 

Cloaca  formation  occasionally  occurs  in  swine.  This 
condition  results  from  fusion  of  the  rectum  and  vagina, 
there  being  but  one  external  opening  common  to  the 
uro-genital  and  digestive  tubes.  This  deformity  does 
not  interfere  with  health,  but  it  practically  prohibits 
breeding.  Although  it  may  be  relieved  by  operation, 
the  value  of  the  animal  usually  does  not  warrant  such 
procedure. 

Injuries  to  the  vagina  are  occasionally  inflicted  during 
parturition,  but  the  condition  is  seldom  recognized  and 
rarely  causes  noticeable  after  effects. 


130  SWINE  DISEASES 

Inflammation  of  the  vagina  usually  accompanies 
metritis.  The  discharge  in  such  cases  is  usually  purulent 
and  the  condition  is  designated  leukorrhea.  Vaginal 
douches  relieve  simple  cases  of  vaginitis,  but  if  the 
primary  disturbance  is  within  the  uterus  it  must  be 
overcome  before  the  vaginitis  will  yield  to  treatment. 

VULVA 

Although  the  location  of  the  vulva  predisposes  it  to 
injury,  such  mishaps  are  not  common. 

Occasionally  the  Bacillus  necrophorus  infects  the 
vulvar  tissue  and  produces  typical  necrobacillosis,  which 
may  terminate  fatally  unless  properly  treated. 

MAMMARY  GLANDS 

Although  the  mammary  glands  are  modified  glands  of 
the  skin,  they  are  essential  to  the  life  of  the  newborn. 
Therefore,  a  discussion  of  the  diseases  liable  to  affect 
these  glands  belongs  properly  with  the  consideration  of 
the  reproduction  organs. 

The  location  of  the  mammse  of  swine  predisposes 
them  to  injury  and  infection  of  various  kinds,  and  in 
addition  the  mammary  gland  contains  a  milk  cistern  which 
is  also  easily  infected.  But  since  swine  are  more  resistent 
to  infection  than  other  domestic  animals,  the  mammary 
disturbances  also  are  less  common  in  swine. 

Mammitis 

Acute  inflammation  of  the  mammary  gland  occurs, 
but  is  rare.  The  usual  cause  is  infection,  but  this  generally 
means  that  the  gland  has  been  injured  and  thus  predis- 
posed to  infection. 

The  affected  gland  is  tumefied,  hot,  and  painful. 
On  sectioning,  varying  quantities  of  milk  and  inflamma- 
tory exudate  escape  from  the  ducts.  The  blood  vessels 
are  gorged  with  blood,  and  the  milk  in  the  larger  ducts 
and  cistern  contains  clots. 

The  affected  sow  refuses  to  allow  her  pigs  to  nurse. 
She  will  change  position  as  frequently  as  they  attempt 


THE  URO-GENITAL  SYSTEM 


131 


it,  and  occasionally  a  sow  is  observed  that  will  purposely 
injure  the  pigs  if  they  persist  in  their  endeavor  to  nurse. 
On  examination,  the  gland  is  found  enlarged,  more 
sensitive  than  normally,  and  if  any  milk  is  forced  out  of 
the  teat  it  will  be  more  or  less  ropy. 

Treatment. — Hot  and  cold  applications  alternated, 
when  possible  to  apply  such   treatment,   will   be  of  as 


Fig.   7.— INFECTION   OF   JWAMJUARY   GLAND. 
A.    Normal    glandular    tissue.     B.    Calcified    areas.     C.    Galactophorous 


much  value  as  any  local  treatment.     The  administration 
of  a  purgative  is  also  advised. 

Botryomycotic  Mammitis 

Botryomycotic    mammitis    occurs    in    swine,    but    is 
not  common.     The  lesions  are  practically  the  same  as 


132  SWINE  DISEASES 

those  described  for  botryomycosis  under  the  heading 
"Sequels  of  Castration,"  on  page  122.  Prognosis  should 
always  be  guarded  in  those  cases  in  which  the  mammary 
gland  is  removed,  as  a  large  percentage  of  the  animals 
die. 

Actinomycotic  Mammitis 

Actinomycotic  mammitis,  in  the  experience  of  the 
writer,  is  more  common  in  swine  than  botryomycotic 
mammitis.  Infection  occurs  through  abrasions  of  the 
skin  surface.  This  condition  is  most  common  in  swine 
that  are  in  pasture  in  stubble  fields.  The  lesions  are  the 
same  as  lesions  of  actinomycosis  of  any  soft  tissue  and 
consist  of  a  dense  surrounding  capsule  of  fibrous  tissue 
inclosing  multilocular  communicating  centers  containing 
a  tenacious,  granular,  creamy-white  pus.  The  actinomy- 
cotic tumefaction  may  become  eroded  and  the  tyical 
actinomycotic  pus  discharged.  Actinomycotic  mam- 
mitis is  characterized  by  the  presence  of  the  tumefaction, 
which  may  be  round  and  have  a  smooth  surface  or  it 
may  be  lobulated.  These  tumefactions  vary  in  size 
from  that  of  a  small  marble  to  masses  larger  than  a 
baseball. 

Ablation  of  the  entire  tumor  is  the  most  rational 
and  successful  manner  of  combating  and  relieving  this 
trouble. 

Tuberculous  Mammitis 

Tuberculous  mammitis  is  relatively  common  in 
swine.  The  infection  of  the  mammae  may  be  due  to  a 
diseased  condition  elsewhere  in  the  body  or  it  may  be 
introduced  through  wounds  from  the  outside. 

The  lesions  are  the  same  as  other  tuberculous  lesions. 

Treatment. — If  the  infection  is  localized  in  the 
mammse  the  disease  may  be  successfully  treated  by 
operation,  but  the  safest  and  most  sanitary  plan  is 
destruction  of  the  animal  and  cremation  of  the  carcass, 
thereby  diminishing  the  possibility  of  spreading  the 
infection. 


THE  UROGENITAL  SYSTEM  133 

Tumors 

Maniinary  tiunor.s  are  rare  in  swine,  though  an 
occasional  papilloma  may  be  observed  upon  the  teat. 
Rarely  do  adenomas  occur  in  the  mammae  of  swine, 
although  a  few  cases  have  been  reported. 


SECTION  IV 
ORGANS  OF  LOCOMOTION 


UNDER  this  heading  will  be  considered  the  dis- 
eases of  the  voluntary  muscles,  bones,  and  joints. 
A  great  variety  of  malformations  of  the  organs 
of  locomotion  have  been  observed  in  swine.  Multi- 
plicity of  legs  or  duplication  of  portions  of  a  leg  are 
relatively  common,  and  fusion  of  parts  ordinarily  separate 
is  occasionally  encountered.  These  abnormalities  may 
be  so  adverse  to  the  existence  of  the  animal  that  it  dies 
soon  after  birth,  or  the  anomaly  may  be  so  slight  that 
the  animal  is  in  no  way  inconvenienced  and  develops 
into  maturity. 

Injuries  of  various  kinds  are  prone  to  damage  and 
possibly  destroy  the  usefulness  of  the  part  affected,  and 
thus  interfere  with  the  locomotion  of  the  animal  to  such 
an  extent  that  it  must  be  sacrificed.  Muscle  wounds 
usually  give  little  trouble  in  swine  because  of  their 
marked  resistance-  to  infection,  while  fractures  are  not 
so  troublesome  in  swine  as  in  the  larger  animals,  and  are 
usually  repaired  rapidly  and  frequently  without  inter- 
vention of  the  surgeon. 

Sore  Feet 

The  feet  of  swine  that  are  kept  on  pavements  or  driven 
long  distances  over  hard  roads  become  sore.  This  con- 
dition is  attracting  the  attention  of  serum  producers 
who  are  required  by  the  government  regulations  to  keep 
the  hyperimmune  swine  on  concrete  or  other  similar 
floors.  Those  producers  depending  upon  tail  bleeding 
are  having  considerable  difficulty  in  keeping  the  hyper- 
immune swine  for  the  required  time  because  it  is  difficult 
to  keep  the  pens  free   from  filth  when  bedding  is    used. 

1.35 


136  SWINE  DISEASES 

Sore  feet  due  to  rough,  hard  roads  and  pens  also 
occasion  some  trouble  in  swine.  This  condition  caused 
more  concern  in  former  times,  when  swine  were  driven 
considerable  distances  to  market,  than  at  the  present 
time.  However,  it  also  is  a  problem  that  confronts  the 
serum  producers. 

About  the  only  treatment  is  to  provide  ample,  clean 
bedding  or  turn  the  swine  out  to  pasture. 

Fatty  Degeneration 

Fatty  degeneration  of  muscle  tissue  has  been  observed 
in  suckling  pigs  by  various  investigators.  This  disease 
or  condition  is  characterized  by  an  extensive  fatty 
degeneration  of  the  muscular  tissue  of  the  entire  body. 
The  cause  of  this  degeneration  is  not  known,  although 
it  may  be  a  sequel  of  inbreeding.  It  affects  pigs  from 
a  few  days  old  to  three  or  four  weeks  of  age.  The  muscle 
has  a  white  appearance,  as  if  it  had  been  cooked.  Similar 
changes  may  also  be  noted  in  the  lymph  glands,  liver, 
and  kidneys.  The  affected  pigs  cease  to  nurse,  lie  on 
the  ground,  are  weak,  and  may  have  diarrhea.  The 
disease  almost  always  terminates  fatally,  the  pigs  some- 
times not  even  struggling  when  they  die,  but  in  other 
instances  convulsions  precede  death.  Thus  far  no 
medicinal  treatment  has  proved  of  value,  but  the  disease 
may  be  prevented  by  proper  care  and  the  frequent 
introduction  of  new  breeding  stock. 

Muscular  Rheumatism 

Rheumatism  may  affect  the  muscular  tissue,  but 
more  frequently  it  affects  articulations  in  swine. 

The  cause  of  muscular  rheumatism  has  not  been 
positively  identified.  No  doubt  undue  exposure  predis- 
poses the  animal  to  this  condition,  but  there  must  also  be 
some  active  cause,  such  as  infection  or  absorbed  injurious 
chemical  substances. 

Lesions. — Muscular  rheumatism  primarily  affects  the 
connective  tissue  of  the  muscles.  The  lesion  consists  of 
a  serous  or  hemorrhagic  infiltration  between  the  muscle 


ORGANS  OF  LOCOMOTION  137 

bundles  and  fibers,  and  rarely  of  necrosis  of  the  intra- 
muscular fibrous  tissue.  The  muscle  fibers  are  affected 
with  parenchymatous  or  fatty  degeneration,  and  the 
surrounding  arterioles  and  capillaries  are  engorged. 

Symptoms. — The  principal  symptom  consists  of 
expression  of  pain,  especially  evident  when  the  animal 
moves.  Locomotion  is  interfered  with,  and  there  is  a 
shifting  lameness.  Some  cases  of  so-called  paralysis 
resulting  in  dragging  of  the  hind  legs  are  probably  mus- 
cular rheumatism.  If  the  disease  is  sufficiently  extensive 
the  affected  animals  refuse  to  eat.  Muscular  rheumatism 
is  differentiated  from  trichinosis  by  the  periodic  shifting 
lameness  of  rheumatism  and  by  the  general  absence  of 
systemic  disturbances.  It  may  be  necessary  to  dis- 
tinguish it  from  rickets,  which  is  not  difficult,  since  the 
latter  is  a  disease  affecting  the  bones. 

Treatment. — Provide  good  quarters  where  the  animal 
will  not  experience  wide  variations  of  temperature  within 
a  short  time.  Laxatives  and  some  form  of  salicylates  or 
their  derivatives  are  usually  of  value,  but  must  be  given 
judiciously  to  avoid  impairment  of  digestion. 

Articular  Rheumatism 

Articular  rheumatism  sometimes  occurs  in  swine. 
This  condition  affects  s\\ane  that  have  been  unduly 
exposed,  but  probably  the  exciting  cause  is  infection. 

Articular  rheumatism  is  essentially  an  inflammation 
of  the  periarticular  structures,  including  the  synovial 
membrane.  The  inflammation  may  be  serous,  fibrinous, 
or  hemorrhagic,  and  in  extreme  cases  it  may  become 
purulent.  The  exudate  is  accumulated  in  the  peri- 
articular structures  and  occasionally  in  tht  joint  cavity. 
Th-  synovia  become  admixed  with  the  inflammatory 
exudate  and  appears  turbid,  bloody,  or  purulent,  and 
may  contain  coagulated  fibrin;  the  articular  surfaces  are 
rough.  In  cases  of  long  standing  the  articulation  is 
surrounded  by  varying  quantities  of  fibrous  tissue  which 
may  cicatrize  and  cause  deformity.  Various  articulations 
are  affected,  but  the  lesions  are  principally  confined  to 
the  carpal,  tarsal,  stifle,  and  fetlock  joints. 


138  SWINE  DISEASES 

Symptoms. — The  onset  of  tliis  trouble  is  sudden. 
The  affected  articulations  become  swollen  and  are  very 
sensitive  to  palpation;  the  animal  refuses  to  place  weight 
on  them  or,  if  compelled  to  do  so,  expresses  pain.  If 
articulations  of  more  than  one  leg  are  simultaneously 
affected  the  animal  remains  lying  down,  arising  only 
after  considerable  urging.  There  is  usually  some  rise  of 
temperature  and  a  diminished  desire  for  food,  or  inappe- 
tence.  The  disease  runs  a  variable  course,  the  attacks 
being  intermittent.  An  attack  usually  continues  for 
about  two  weeks,  then  the  animal  apparently  recovers, 
but  sooner  or  later  the  attacks  reccur. 

Treatmient.^ — The  treatment  for  articular  rheumatism 
is  practically  the  same  as  for  muscular  rheumatism. 
Provide  good  quarters,  and  administer  laxatives  and 
salicylates.  The  outcome  of  the  disease  is  uncertain, 
and  if  the  animals  are  in  butcher  condition  they  should 
be  disposed  of  several  days  after  the  cessation  of  the 
symptoms  of  an  attack. 

Rickets  or  Rachitis 

This  is  essentially  a  disease  due  to  some  disturbance 
of  metabolism,  but  since  the  lesions  are  manifested 
principally  in  the  bones  it  may  be  considered  in  this 
chapter. 

Rickets  is  relatively  common  in  swine,  and  is  confined 
principally  to  young  pigs.  The  disease  is  more  prevalent 
in  some  localities  than  in  other  sections  of  the  country, 
and  the  condition  appears  to  prevail  more  extensively 
during  some  years  than  others. 

Etiology. — The  specific  exciting  cause  of  rickets  is 
unknown.  The  condition  is  due  to  an  insufficient  deposit 
of  lime  in  the  bone.  It  may  be  due  to  an  insufficient 
lime  in  the  food,  to  intoxication  which  may  neutralize  or 
prevent  the  deposit  of  lime  in  the  bone,  or  infection  may 
he  a  causative  factor. 

Lesions. — The  condition  is  not  confined  to  any 
[)articular  ty])e  or  group  of  bones;  however,  the  lesions 
are  usually  most  pronounced  in  the  long  bones  of  the 


ORGANS  OF  LOCOMOTION  139 

legs,  which  are  bent  or  curved,  the  animal  being  "bow 
legged."  The  bones  are  soft  and  so  spongy  that  they 
may  be  cut  readily  with  a  knife.  The  epiphyses  of  the 
long  bones  are  enlarged  and  irregularly  club-shaped, 
while  the  shaft  is  also  irregularly  thickened.  There  is 
a  subperiosteal,  spongy  layer.  The  yellow  marrow  is 
red  in  color  and  is  of  a  gelatinous  consistency.  There 
may  be  ulceration  of  articular  surfaces,  and  the  flat 
bones  of  the  cranium  and  pelvis  may  be  thickened  and 
rarefied.  The  nares  and  mouth  may  be  practically 
obliterated  by  the  enlarged  rarefied  nasal  bones  and 
hard  palate;  the  teeth  may  appear  deep-set  on  account 
of  the  tumefaction  of  the  alveolar  tissue.  In  advanced 
cases,  lesions  may  be  found  elsewhere  causing  disturb- 
ances of  the  digestive  or  respiratory  system. 

Symptoms. — The  first  evidence  of  the  disease  is 
weakness,  diminished  or  depraved  appetite,  and  diarrhea. 
But  lameness  or  stiffness  of  gait  succeeded  by  bending 
or  arching  of  the  bones  is  the  first  positive  indication  of 
rickets.  At  this  stage  the  lying  posture  is  almost  con- 
tinuously assumed.  When  the  affected  animals  are 
made  to  arise  they  complain  of  pain  by  grunting  and 
squealing,  and  not  infrequently  they  will  walk  on  the 
carpal  joints.  There  may  be  nervous  disturbances 
evidenced  by  dizziness,  somnolence,  and  convulsions. 
As  the  disease  progresses  the  enlarged  epiphyses  become 
evident  and  appear  as  a  swollen  condition  of  the  articu- 
lation. Similar  bony  enlargements  may  also  occur 
elsewhere.  The  bulging  of  the  long  bones  of  the  front 
legs  exert  undue  pressure  upon  the  ribs,  which  results 
in  disturbed  respiration,  and  the  vertebral  column  is 
variously  curved,  upward,  downward,  or  laterally. 

This  disease  is  of  a  chronic  nature  and  continues  for 
months  unless  death  intervenes  early,  which  is  exceptional. 
Diagnosis  is  not  difficult  after  the  changes  in  the  bones 
are  evident,  while  the  chronic  nature  of  rickets  is  sufficient 
to  differentiate  this  condition  from  articular  rheumatism. 
Tuberculous  osteitis  is  differentiated  from  rickets  by  the 


140  SWINE  DISEASES 

limited  infection  and  the  less  extensive  tumefaction,  and 
lack  of  density  of  the  affected  bones. 

Treatment. — Treatment  of  rachitic  swine  is  advised 
only  in  the  early  stages  of  the  disease.  Those  in  the 
advanced  stages  should  be  destroyed.  The  first  thing  to 
do  is  to  place  the  animals  in  sanitary  quarters,  then 
medicinal  treatment  consists  of  administering  lime  in 
some  form.  Prepared  chalk  may  be  used.  Bone  meal 
is  also  of  value,  precipitated  calcium  phosphate  is  highly 
recommended  by  some,  and  calcium  chlorate  may  be 
found  serviceable.  Preventive  measures,  as  proper  feed- 
ing and  care,  practically  insure  against  the  occurrence  of 
this  disease  in  swine. 

Osteomalacia 

This  is  a  disease  characterized  by  softening  and 
fragility  of  bones.  Osteomalacia  is  also  a  disease  of 
disturbed  metabolism  which  evidences  itself  by  lesions 
of  the  bones.  It  is  not  of  common  occurrence  in  swine, 
and  when  found  is  due  to  an  insufficient  amount  of  lime 
in  the  regimen,  in  a  form  capable  of  assimilation. 

The  bones  most  frequently  involved  are  those  of  the 
extremities,  ribs,  vertebral  column,  skull,  and  pelvis. 
The  affected  bones  become  enlarged  and  less  dense,  the 
marrow  cavity  of  long  bones  is  increased  in  size  and 
filled  with  a  gelatinous,  usually  hemorrhagic  marrow, 
while  the  osseous  tissue  is  less  dense  and  more  fragile. 
Fractures  are  very  common. 

The  disease  is  usually  initiated  by  digestive  dis- 
turbances, which  is  succeeded  by  emaciation,  impaired 
and  usually  difficult  locomotion,  fractures,  and  various 
deformities.  The  disease  finally  assumes  a  chronic 
form,  evidencing  periods  of  temporary  improvement  and 
relapses.  This  is  essentially  a  disease  of  mature  animals, 
and  this  factor  is  of  value  in  differentiating  osteomalacia 
from  rickets.  The  prognosis  is  favorable  in  cases  showing 
no  marked  enlargement  of  bones  or  deformity,  and 
unfavorable  in  those  cases  showing  deformity. 


ORGANS  OF  LOCOMOTION  141 

Treatment. — Provide  proper  food  and  surroundings, 
and  administer  lime  salts,  as  outlined  in  the  foregoing 
for  rickets. 

Purulent  Osteomyelitis 

Inflammation  of  the  bone  marrow  occurs  in  swine. 
This  condition  is  sporadic,  and  is  most  frequently  ob- 
served in  young  animals. 

Etiology. — Purulent  osteomyelitis  is  caused  by  infec- 
tion. Various  pyogenic  microorganisms  have  been  identi- 
fied, such  as  Staphylococcus  pyogenes  aureus  and  albus. 
Streptococcus,  and  in  one  instance  the  Bacillus  pyocy- 
aneus,  was  isolated  and  apparently  occurred  in  pure  cult- 
ure. There  is  probably  some  predisposing  cause,  such  as 
hog  cholera,  but  all  of  the  cases  observed  have  shown  no 
lesions  of  cholera  or  other  than  the  primary  disease. 

Lesions. — The  ribs  are  most  frequently  affected. 
The  bone  marrow  becomes  hyperemic  and  invaded  with 
leukocytes  and  inflammatory  products,  and  the  internal 
pressure  causes  the  bone  to  become  enlarged  and  the 
marrow  cavity  to  be  increased  in  size.  The  marrow  and 
the  inflammatory  exudate  disintegrate  and  form  pus. 
As  pus  is  produced  the  bone  becomes  larger  and  round, 
although  it  may  show  some  irregularities  in  shape.  The 
pus  in  the  marrow  cavity  may  erode  the  bone  tissue  and 
discharge,  thus  producing  a  fistulous  tract,  but  more 
frequently  the  pus  becomes  caseous  and  may  later 
undergo  calcification.  Suppurative  processes  are  rarely 
observed  in  other  bones. 

Symptoms. — There  is  little  outward  manifestation 
of  purulent  osteomyelitis  other  than  the  formation  of  a 
barrel  chest  (the  ribs  form  a  wider  arch,  the  thorax 
appearing  almost  round  in  cross-section),  and  the  promin- 
ent tumefied  ribs.  If  the  affected  animal  is  in  good  con- 
dition the  ribs  are  not  visible.  These  cases  are  usually 
of  long  standing,  and  the  disease  is  essentially  chronic. 
Antemortem  diagnosis  is  rarely  made.  Purulent  osteo- 
myelitis can  be  distinguished  from  osteomalacia  by  the 
localization  of  the  process  in  the  ribs. 

Treatment. — Medicinal  treatment  is  of  no  value. 


142  SWINE  DISEASES 

Trichinosis 

Trichinosis  assumes  two  forms,  intestinal  and  mus- 
cular. Both  types  occur  in  the  same  animal,  the  intestinal 
preceding  the  muscular  form. 

This  disease  is  quite  prevalent,  particularly  in  North 
America.  From  two  to  eight  per  cent  of  American 
hams  imported  into  Germany  have  been  found  infested. 
The  disease  is  less  prevalent  in  Europe,  or  at  least  the 
statistics  so  indicate. 

The  cause  of  trichinosis  is  the  Trichinella  spiralis. 
This  is  a  small,  round  worm,  the  adult  rarely  exceeding 
one-twelfth  of  an  inch  in  length.  The  life  cycle  of  the 
parasite  is  as  follows: 

The  larvae  gain  entrance  to  the  digestive  tract  in 
meat,  where  the  surrounding  capsule  is  dissolved  by  the 
digestive  juices,  and  thus  are  liberated  within  twenty- 
four  hours.  They  pass  into  the  small  intestine,  where 
they  become  sexually  mature  in  about  three  days.  About 
five  days  after  copulation,  or  within  ten  or  twelve  days 
after  ingestion,  the  pregnant  female  and  the  male  are 
found  in  the  crypts  of  Lieberkiihn  and  the  female  begins 
to  deposit  her  young  in  the  form  of  living  embryos. 
This  process  is  continued  by  the  female  for  from  six  to 
eight  weeks,  during  which  time  she  produces  from  eight 
to  fifteen  thousand  young.  A  few  of  the  embryos  pass 
out  with  the  feces,  but  most  of  them  pass  through  the 
tissue  of  the  intestine,  some  of  them  gaining  entrance  to 
capillary  lymph  and  blood  vessels,  while  others  wander 
through  the  tissue.  Those  passing  into  the  lymphatics 
ultimately  reach  the  blood  stream,  as  do  those  passing 
directly  into  the  blood  capillaries,  and  finally  they  are 
distributed  by  the  blood  or  by  direct  migration  to  all 
parts  of  the  body.  The  embryos  thus  distributed  pass 
into  various  tissues,  but  as  a  rule  only  those  entering 
the  muscular  tissue  survive  and  develop.  The  embryo 
matures  into  a  larva  in  the  muscle  in  a  period  of  about 
two  months;  by  this  time  the  irritation  produced  has 
resulted  in  the  formation  of  a  capsule.  These  encapsu- 
lated larvae  will  retain  their  vitality  in  swine  for  a  period 


ORGANS  OF  LOCOMOTION  143 

of  about  eleveD  years,  but  the  capsule  and  some  of  the 
interior  of  the  cyst  undergo  calcification,  the  process 
beginning  about  one  or  one  and  a  half  years  after  encap- 
sulation. 

Swine  become  infested  by  eating  trichinous  flesh  of 
pigs,  rats,  or  other  animals,  or  from  eating  the  excretions 
of  infested  animals.  All  breeds  of  swine,  regardless  of 
age,  are  equally  susceptible.  Trichinosis  is  most  preva- 
lent in  swine  kept  in  small  pens,  especially  when  sani- 
tation is  not  observed. 

Lesions. — The  adults  produce  an  intestinal  catarrh 
which  is  most  evident  in  the  proximal  portion  of  the  in- 
testine. Soon  after  the  embryos  begin  to  migrate  the 
mesenteric  lymphatic  glands  become  enlarged,  and  there 
may  be  pulmonary  congestion  and  parenchymatous 
degeneration  of  the  liver  and  kidneys.  The  affected 
muscle  first  becomes  swollen,  and  appears  of  a  gray  color. 
About  eight  weeks  after  the  embryos  begin  to  migrate, 
small  gray  or  grayish-white  specks  may  be  detected  in 
the  muscle  tissue.  This  condition  is  especially  e\'ident 
in  the  diaphragm,  intercostal  muscles,  muscles  of  the 
cervical  region,  and  tongue.  If  the  lesions  are  of  long 
standing  they  will  contain  calcium  salts,  which  may  be 
detected  as  small,  gritty  masses.  Microscopically,  in 
the  first  year  of  muscular  trichinosis  the  larvae  can  be 
readily  detected  as  small,  coiled,  thread-like  worms 
within  a  capsule. 

Symptoms. — Clinical  trichinosis  has  been  observed 
only  in  experiments,  or  at  least  the  disease  has  not  been 
recognized  by  the  clinician.  Experimentally,  intestinal 
trichinosis  becomes  e^ddent  in  from  three  to  six  days 
after  infestation.  The  disease  is  manifested  by  the 
following  symptoms:  inappetence,  vomition,  diarrhea, 
colic,  arched  back,  unwillingness  to  move,  and  rapid 
emaciation.  Evidence  of  muscular  trichinosis  appears 
in  about  two  weeks,  and  is  manifested  by  the  following 
symptoms:  rubbing  against  posts  or  other  objects, 
stiffness,  assumption  of  the  lying  posture  the  greater 
part  of  the  time,  dyspnea,  dysphagia,  and  rise  of  tem- 


144  SWINE  DISEASES 

perature.  These  symptoms,  in  the  order  mentioned, 
continue  for  four  to  six  weeks,  and  the  affected  animal 
apparently  recovers.  Diagnosis  of  trichinosis  may  be 
possible  clinically,  but  the  absolute  diagnosis  depends 
upon  a  miscroscopic  detection  of  the  parasite. 

Treatment. — Medicinal  treatment  may  be  of  some 
value  in  eliminating  the  adults  from  the  intestine,  but 
the  disease  is  rarely  diagnosed  before  death.  The 
muscular  form  of  the  disease  is  not  relieved  by  treatment. 
Prophylactic  measures,  such  as  general  sanitation  and 
eradication  of  rats,  should  be  instituted. 

Cysticercosis  (Measles) 

Cysticercosis  is  a  condition  due  to  the  invasion  and 
developenmt  of  the  cystic  form  of  a  tapeworm.  This 
condition  prevails  more  or  less  in  the  swine  of  practically 
all  countries.  Cysticercosis  in  the  muscular  tissue  of 
swine  is  due  to  the  cystic  form  of  the  Taenia  solium;  the 
cystic  form  of  this  parasite  being  designated  Cysticercus 
cellulose. 

Etiology. — The  life  cycle  of  the  Taenia  solium  is  as 
follows.  The  ova  of  the  adult,  which  resides  in  the 
intestinal  tract  of  man,  is  eliminated  in  the  feces.  Swine 
eat  the  contaminated  feces  and  the  digestive  juices 
dissolve  the  shell  of  the  tapeworm  ova  and  liberate  a 
six-hooked  embryo.  The  embryos  bore  through  the  walls 
of  the  stomach,  some  of  them  entering  the  blood  vessels, 
and  are  thus  distributed  by  migration  and  the  circulation 
of  the  blood  to  all  parts  of  the  body.  Those  depositing 
elsewhere  than  in  the  muscular  tissue  do  not  as  a  rule 
develop.  The  development  of  the  parasite  is  rather 
slow.  The  embryo  assumes  the  form  of  a  cyst  and  in 
twenty  days'  time  is  about  the  size  of  an  ordinary  pin- 
head.  By  this  time  the  head  of  the  future  tapeworm  is 
visible  as  a  mere  point.  About  two  months  after  the 
embryo  lodges  in  the  muscle  it  has  attained  the  size  of  a 
small  pea,  and  in  three  months  the  embryo  has  matured, 
as  is  evidenced  by  the  presence  of  sucker  disks  and  a 
rostellum  of  booklets  on  the  head  of  the  future  tapeworm. 


ORGANS  OF  LOCOMOTION 


145 


Should  a  human  being  consume  uncooked  swine  flesh 
containing  one  of  these  mature  bladder  worms  the 
digestive  juices  would  dissolve  the  capsule  and  liberate 
the  scolex,  which  would  attach  itself  to  the  intestinal 
mucosa.  From  three  to  five  months  are  required  from 
the  time  of  ingestion  of  the  bladder  worm  by  the  human 
until  ripe  segments  are  eliminated.  One  ripe  segment 
contains  from  ten  to  thirtv  thousand  ova. 


Fiff.  8.— CYSTICEKCOSIS    (Pork  3Ieasles). 
A.  Muscle.     B.  Fat.     C.  Cysticertus  ceUulosae. 


Swine  become  infested  by  ingesting  water  or  food 
contaminated  with  the  ova  of  the  Taenia  solium.  This 
condition  occurs  only  in  hogs  that  consume  human 
excrements,  and  young  swine  are  more  susceptible  to 
this  condition  than  are  the  aged  animals. 

Lesions. — The  presence  of  the  cysts  typifies  Cys- 
ticercus  cellulosse.  These  cysts  vary  in  size  from  visible 
points  to  small  beans.     They  are  usually  oval  in  shape, 


146 


SWINE  DISEASES 


and  the  scolex  can  readily  be  recognized  witlnn  as  a  white 
point  or  bod3\  The  cyst  is  surrounded  by  a  tliin  capsule 
and  contains  one  head  and  a  thin,  watery  fluid.  After 
the  cyst  has  persisted  for  one  year  or  longer  it  degener- 
ates, the  content  becoming  purulent,  and  later  calcifying. 
Symptoms. — Cysticercosis  in  swine  is  rarely  recog- 
nized  clinically.     The   migration   into   and   irritation   of 


lis.    9.— ri;j>tN€LI>Ari<JI)    llltliOiMA. 


the  muscle  may  cause  muscular  soreness  and  disturbed 
locomotion  which,  depending  upon  the  extent  of  the 
invasion,  may  be  associated  with  inappetence,  unthrifti- 
ness,  and  emaciation. 

Treatment. — Prophylaxis  consists  of  preventing  con- 
tamination of  swine  food  and  water  with  human  excre- 
ments.    No  curative  treatment  is  available. 

Sarcosporidiosis 

Sarcosporidiosis  is  a  disease  of  muscular  tissue  due 
to  a  parasite,  the  Sarcosporidia.  This  condition  is  rela- 
tively common  in  sw^ine.  Generally  speaking,  sarcos- 
poridiosis is  not  considered  a  disease  of  any  importance, 
but  frequently  swine  are  affected  with  a  weakness  of  the 
muscles  of  the  back  that  causes  them  to  drag  the  hind 


ORGANS  OF  LOCOMOTION  147 

legs.  Although  no  (jpportuuity  for  the  examination  of 
the  muscle  from  these  cases  has  arisen,  the  writer  has 
thought  the  condition  is  probably  due  to  sarcosporidiosis. 

Etiology. — The  Sarcocystis  miescheri  is  the  cause  of 
sarcosporidiosis.  The  exact  life  cycle  of  this  parasite  is 
unknown. 

Lesions. — The  cysts  are  usually  so  small  that  they 
cannot  be  detected  without  the  use  of  a  microscope. 
However,  an  unusual  specimen  was  obtained  by  York 
at  an  abattoir  in  Chicago  in  which  the  cysts  could  be 
readily  detected  as  grayish- white  ovoid  patches.  Micro- 
scopically, the  parasites  are  found  within  the  muscle 
sarcolemnia.  They  appear  to  destroy  or  displace  the 
muscle  substance,  the  fiber  being  entirely  severed,  the 
sarcolemma  alone  remaining  intact.  The  sarcocysts 
contain  many  round  or  oval  bodies,  the  sporozoites. 
The  cysts  undergo  degeneration  and  calcify,  but  at 
what  age  these  changes  occur  has  not  been  determined. 

Symptoms. — The  disease  has  not  been  recognized 
clinically,  but  no  doubt  infestation  would  interfere  with 
the  muscle  function. 

Treatment. — Therapeutic  treatment  is  not  available, 
and  in  the  absence  of  a  definite  knowledge  of  the  life 
cycle  of  the  parasite,  preventive  measures  are  only 
problematic.     General  sanitation  should  be  maintained. 

Tumors 

An  occasional  tumor  is  encountered  that  has  invaded 
the  muscular  or  osseous  tissue  of  swine.  But,  generally 
speaking,  tumors  of  these  structures  are  of  little  signifi- 
cance. 


SECTION  V 
THE  SKIN 

DISEASES  of  the  skin  are  probably  not  so  common 
in  swine  as  in  other  domestic  animals.  Because 
of  the  location  of  the  skin  it  is  subject  to  a 
variety  of  injuries  of  various  kinds,  but  fortunately 
swine  are  not  very  susceptible  to  wound  infections  and 
therefore  cutaneous  lesions  heal  promptly  and  with 
little  inconvenience  to  the  afflicted  animal. 

Erythema 

Erythema  is  a  name  applied  to  the  condition  resulting 
from  congestion  of  the  skin.  It  is  quite  common,  par- 
ticularly in  swine  having  little  or  no  pigment  in  the  skin. 
It  is  also  a  common  condition  in  some  infectious  diseases, 
such  as  swine  plague  and  hog  cholera. 

Etiology. — Simple  erythema  in  swine  is  most  fre- 
quently the  result  of  sunshine  but  may  be  due  to  contact 
with  some  irritant.  In  some  instances  erythema  may 
be  caused  by  ingested  chemicals  that  have  a  special 
selective  action  on  the  skin  or  are  eliminated  by  the  skin. 

Lesions.— Engorgement  of  the  superficial  vessels 
and  redness  are  the  only  demonstrable  lesions. 

Symptoms. — Redness,  and  perhaps  pruritis,  are  the 
principal  symptoms. 

Treatment. — Remove  the  cause,  and  the  disturbance 
will  cease  to  exist. 

Sunburn 

Swine  having  little  pigment  in  the  skin  are  injured 
by  sunlight.  In  some  sections  it  is  not  profitable  to 
raise  white  pigs  because  of  the  irritation  of  the  skin  by 
the  sun  and  the  production  of  dermatitis. 

Sunburning  is  a  type  of  dermatitis  characterized  by 
erythema,  tumefaction,  and  desquamation  of  the  super- 

149 


150  SWINE  DISEASES 

ficial  layers  of  the  epidermis.  In  long-continued  cases 
the  skin  becomes  thickened,  due  to  the  formation  of 
fibrous  tissues.  Swine  affected  with  dermatitis  do  not 
thrive,  and  they  evidence  a  harsh  skin  and  bristly  coat. 
Treatment. — The  treatment  of  these  cases  is  simple, 
as  about  all  that  is  required  is  to  shield  the  animals  from 
the  direct  light  of  the  sun.  Should  the  inflammatory 
process  be  well  marked,  cooling  antiseptic  solutions  may 
be  applied. 

Freezing 

Pigs  farrowed  in  midwinter  in  the  northern  portion 
of  the  temperate  zone,  where  not  properly  housed,  are 
frequently  frozen.  The  ears  and  tail  are  most  affected 
because  of  the  large  surface  exposure  and  distal  location 
where  the  circulation  is  diminished.  In  some  instances 
the  tissues  are  destroyed  by  the  low  temperature,  and 
slough,  while  in  other  cases  the  ears  or  tail,  or  both,  are 
frosted  only  and  an  inflammatory  reaction  is  established 
resulting  in  an  engorgement  and  tumefaction  of  the 
I)art.  Later  the  skin  desquamates  and  the  parts  are 
tender  when  palpated. 

Transportation  of  market  hogs  in  open  stock  cars 
during  very  cold  weather  is  responsible  for  the  freezing 
of  the  surface  skin.  The  skin  sometimes  evidences 
the  lesions  in  strips  corresponding  to  the  openings  between 
the  boards  on  the  car.  The  lesions  are  similar  to  those 
described  in  small  pigs. 

Treatment. — This  consists  of  protection  against 
furthur  freezing  and  the  local  application  of  protectant 
dressings,  as  in  ordinary  wounds. 

Hemorrhage 

Cutaneous  hemorrhage  in  which  the  extra vasate  is 
retained  in  the  skin  is  relatively  common  but  is  practically 
always  associated  with  specific  infective  diseases,  seldom 
occurring  as  simple  cutaneous  hemorrhage. 


THE  SKIN  151 

Urticaria 

Urticaria  is  a  s'kin  disease  characterized  by  the  forma- 
tion of  pruritic  wheals.  It  is  not  common  in  swine  and 
when  occurring  is  usually  found  in  young  pigs. 

Etiology. — Urticaria  is  of  systemic  origin.  It  is 
usually  associated  with  digestive  derangement,  but  may 
be  caused  by  filth  and  the  irritation  caused  by  lice. 

Lesions  and  Symptoms. — The  typical  lesions  are 
red,  circumscribed  blotches  that  are  hot  and  pruritic. 
Because  of  the  pruritis  the  pig  rubs  the  skin  and  may 
produce  abrasions  from  which  serum  and  blood  may 
escape.  The  disease  usually  terminates  in  recovery  on 
the  second  or  third  day,  although  in  severe  cases  pustular 
formation  may  follow. 

Treatment. — Clean  the  swine  and  the  premises,  and 
administer  a  saline  purgative,  such  as  Epsom  salt. 

Eczema 

Eczema  is  an  inflammation  of  the  skin  characterized 
by  multiform  lesions.  Though  this  disease  occurs  in 
swine,  it  is  not  very  prevalent. 

Etiology. — Eczema  in  swine  is  apparently  a  disease 
of  filth.  Weak,  anemic  pigs  are  much  more  susceptible 
than  strong  and  otherwise  healthy  animals.  The  specific 
exciting  cause  is  not  known. 

Lesions  and  Symptoms. — Typical  eczema  is  char- 
acterized by  the  following  lesions,  which  occur  in  the 
order  mentioned:  erythema  and  papulovesicular  eruption, 
which  may  or  may  not  be  succeeded  by  the  formation  of 
pustules.  The  contents  of  the  vesicles  and  pustules 
become  desiccated  and  accumulate,  thus  forming  scabs. 
There  is  pruritis  practically  throughout  the  entire  course 
of  the  disease*.  As  the  disease  progresses  the  skin  becomes 
thickened,  leathery,  and  cracks,  the  crevices  or  rhagades 
extending  deeply  and  from  which  more  or  less  blood 
escapes. 

Eczema  is  differentiated  from  parasitic  dermatitis  by 
the  absence  of  the  parasites.     It  is  essentially  a  chronic 


152 


SWINE  DISEASES 


disease;  there  may  be  repeated  attacks.     The  disease  as 
a  rule  is  not  fatal  in  swine. 

Treatment. — Remove  all  influences  that  predispose 
to  the  condition.  Prevent  injury  from  rubbing.  Topical 
application  of  soothing  agents  may  be  used,  but  their 


■a.  *&■'■>-         \  ; 


I  i«.    10.— ELEPHANTIASIS. 
A.   Granular  papillomatous,    depilated  areas.     B.   Khagades   or 


crevices. 


value  is  doubtful.  See  that  the  animals  obtain  and 
digest  their  food  properly.  A  good,  brisk  purgative 
occasionally  will  be  of  value. 

Dermatitis  Granulosa 

A  granular  skin  eruption  has  been  identified  in  swine. 
The  condition  occurs  in  patches  on  the  ears,  back,  and 
croup,  and  is  probably  infectious. 

This  condition  has  responded  quickly  to  treatment 
with  antiseptics. 


THE  SKIN  153 

Necrobacillosis,  Actinomycosis 

Necrobacillosis  is  a  very  common  cutaneous  disease 
in  swine.  Cutaneous  actinomycosis  and  tuberculosis 
occur  less  frequently.  These  conditions  of  the  skin  will 
receive  consideration  under  the  special  tof)ics  of  necro- 
bacillosis, actinomvcosis,  and  tuberculosis,  in  Section 
VIII. 

Tumors 

Pigmented  moles  are  of  frequent  occurrence  in  the 
skin  of  swine.  These  moles  are  sometimes  pigmented 
with  melanin,  and  when  interfered  with  develop  into 
maHgnant  melanosarcomas.  Many  pigmented  papil- 
lomas and  papillo-fibromas  are  also  encountered  in  the 
skin  of  swine,  while  multiple  fibromas  have  been  observed, 
they  are  not  at  all  common.  More  rarely  have  primary 
or  even  secondary  carcinomas  and  epitheliomas  been 
recorded  as  cutaneous  tumors  in  swine. 

Parasites 

Swine  harbor  many  cutaneous  parasites,  some  of 
which  are  exceedingly  detrimental  to  the  health  of  the 
animals. 

Of  the  dipterous  group  one  only,  the  Campsomyia 
macellaria  (screw-worm),  requires  special  mention.  In 
some  sections  these  parasites  cause  considerable  damage 
and  some  fatalities.  The  larvae  only  are  parasitic,  the 
adult  female  depositing  the  ova  in  wounds  or  damaged 
tissue.  The  ova  hatch  in  from  one  to  ten  hours  and 
immediately  begin  to  burrow  into  the  surrounding 
tissues.  The  fully  developed  larvse  are  about  one- 
half  of  an  inch  long  and  about  one-third  the  diameter 
of  a  lead  pencil.  The  damage  consists  not  only  of 
mechanically  lacerating  the  tissues  but  also  of  carrying 
infection  into  the  surrounding  tissues.  The  larvfe 
remain  in  the  tissue  from  four  to  six  days,  then  drop  to 
the  ground,  where  they  undergo  the  pupal  metamor- 
phosis. 

The  time-honored  treatment  consists  of  curetting  the 
wound,  thus  removing  all  the  larvae  possible.     It  may  be 


154  SWINE  DISEASES 

necessary  to  apply  chloroform  or  some  penetrating  anti- 
septic to  cause  the  larvae  in  the  deeper  tissues  to  migrate  to 
the  surface,  or  at  least  to  move  energetically  in  order  that 
they  may  be  located  and  removed.  The  wound  should 
be  properly  dressed  and  protected  against  future  infesta- 
tion. It  is  always  well  to  observe  the  wound  on  the 
second  day  to  make  certain  that  all  larvae  have  been 
removed.  However  clinicians  report  that  this  line  of 
treatment  is  wholly  ineffective,  claiming  better  results  are 
obtained  from  the  treatment  for  screw- worm  in  festation 
given  on  page  123. 

Flea  Infestation 

Representatives  of  the  order,  Siphonaptera,  constantly 
inhabit  hog  houses  and  pens  in  some  sections  of  the 
country.  These  parasites  are  blood  suckers  and  obtain 
their  nourishment  directly  from  the  swine,  but  do  not 
appear  to  cause  any  serious  trouble.  No  doubt  they 
produce  some  irritation  where  they  pierce  the  skin,  and 
swine  thrive  better  in  their  absence.  Fleas  breed 
in  filth,  the  ova  being  deposited  in  fecal  matter  or 
other  filth.  The  larval  and  pupal  stages  also  take  place 
in  filth  and  in  the  soil,  the  entire  cycle  from  adult  to  adult 
requiring  about  one  month. 

Fleas  may  be  lessened  in  number  and  ultimately 
eradicated  from  most  premises  by  persistent  cleanliness 
and  by  dipping  the  swine  in  some  standard  dip  every 
ten  days  for  a  period  of  six  weeks. 

Lousiness  (Phthiriasis) 

Phthiriasis,  or  lousiness,  is  the  most  common  para- 
sitic disease  of  swine.  The  hog  louse,  Hematopinus  suis, 
is  a  blood-sucking  louse  and  one  of  the  largest  of  known 
lice.  The  adult  ovigerous  female  cements  the  ova  on 
the  hair  behind  the  ears,  in  the  flank  region,  and  else- 
where. The  ova  hatch  into  small  lice  in  from  ten  days 
to  two  weeks.  These  lice  do  damage  by  direct  abstrac- 
tion of  blood  and  by  irritation  of  the  skin,  which  causes 
more  or  less  of  pniritis.     This  makes  the  swine  restless 


THE  SKIN  155 

and,  not  receiving  their  proper  rest,  thej'  probably  do 
not  do  as  well  as  they  otherwise  would. 

It  is  not  a  difficult  matter  to  eradicate  lice,  but  their 
permanent  elimination  from  swine  entails  continued 
vigilance.  Where  large  numbers  of  swine  are  infested 
the  most  economical  plan  is  to  put  in  a  dipping  vat 
and  dip  the  hogs  every  ten  daj^s  for  three  or  four 
dippings.  In  the  meantime  the  sleeping  quarters 
should  be  cleaned  and  .  dipping  solution  used  here 
as  a  spray.  If  there  are  only  a  few  swine  to  treat, 
hand  dressing  with  some  standard  dip  is  the  most  eco- 
nomical method  of  treating  them,  of  if  the  swine  have  a 
tank  or  place  where  they  wallow,  some  dipping  solution 
may  be  placed  therein.  The  swine  thus  dip  themselves 
and  destroy  the  lice. 

The  rubbing  post  has  been  used  with  fair  success  as  a 
means  of  holding  louse  infection  in  check.  One  or  more 
posts  are  set  in  the  pens  and  ropes  wound  tightly  around 
them  for  a  distance  of  two  feet  from  the  ground.  These 
ropes  should  be  moistened  with  crude  petroleum  from  time 
to  time.  The  swine  will  annoint  themselves  and  destroy 
most  of  the  lice  by  rubbing  themselves  against  these  posts. 

Mange 

Mange,  or  infestation  of  swine  with  some  Acari  or 
mange  parasites,  is  not  a  rare  condition  in  this  country, 
where  two  forms  of  mange  occur — sarcoptic  mange  and 
demodectic  mange. 

Sarcoptic  Mange 

Sarcoptic  mange  is  enzootic  in  certain  sections.  It  is 
caused  by  infestation  with  the  Sarcoptes  scarbiei,  var. 
suis.     The  life  cycle  of  this  jiarasite  is  as  follows: 

The  ovigerous  female  burrows  into  the  skin,  forming 
galleries  in  which  she  deposits  her  eggs,  usually  about  fifteen 
in  number.  The  ova  hatch  in  from  five  to  ten  days  into 
six-legged  asexual  larvae  which  may  remain  in  the  gal- 
leries or  pass  out  under  the  scabs,  and  in  two  to  three 
days    moult    into    nymphse.     The    nympha?    have    four 


156  SWINE  DISEASES 

pairs  of  legs,  but  they  have  no  sexual  organs.  In  two  or 
three  days  the  nymphse  moult  and  the  sexually  matured 
males  and  females  come  forth.  The  sexuallj^  matured 
parasites  mate,  and  in  about  three  to  five  days  the 
ovigerous  female  is  found  in  the  gallery  in  the  skin, 
ovulating.  Thus  the  entire  life  cycle  does  not  exceed 
twenty-five  days,  and  under  the  most  favorable  condi- 
tions may  be  accomplished  in  fifteen  days.  From  each 
ovulation  about  five  males  and  ten  females  are  produced, 
and  if  the  reproduction  were  to  go  on  unhindered  for  three 
months,  the  total  reproduction  would  approximate 
1,500,000  parasites.  The  adults  are  mere  specks,  barely 
visible  to  the  unaided  eye. 

Swine  become  infested  from  infested  premises  or  from 
infested  swine.  Premises  may  remain  infested  for  six 
months  or  even  longer. 

Lesions.— The  lesions  produced  by  the  Sarcoptes 
are  practically  confined  to  the  skin;  however,  secondary 
lesions,  as  emaciation,  may  arise.  The  parasite  obtains 
tissue  juice  by  pricking  the  skin  with  its  stylet.  The 
stylet  injury  produces  erythema,  succeeded  by  the  forma- 
tion of  vesicles,  which  rupture,  the  vesicular  fluid  drying 
and  forming  a  scab  beneath  which  the  parasites  are 
found.  Scabs  are  of  varying  thickness,  and  accumulate 
wherever  the  parasites  are  found  unless  the  affected  ani- 
mal rubs  them  off.  Galleries  are  formed  within  the  skin, 
and  this  also  adds  to  the  irritation.  The  accumulated 
dry  scabs  break  and  damage  the  hair  more  or  less,  which 
falls,  leaving  the  parts  affected  practically  hairless.  The 
irritation  causes  inflammation,  and  this  results  in  fibrous 
proliferation  and  thickening  of  the  skin.  The  thickened, 
leathery  skin  loses  its  pliability  and  becomes  fissured  or 
cracked.  In  long-continued  cases  the  animals  become 
emaciated. 

Synaptoms.^ — Intense  pruritus,  especially  around  the 
ears  and  eyes,  and  the  finding  of  papules,  vesicles,  and 
scabs  are  the  first  evidences  of  scabies.  Later  there  is 
depilation  and  thickening  of  the  skin,  with  the  accompany- 
ing rhagades.     The  disease  will  probably  affect  all  the 


THE  SKIN  157 

swine  that  have  been  kept  in  one  lot.  The  finding  of  the 
parasite  is  positive  evidence  upon  which  to  base  a  diag- 
nosis. 

Treatment. — Sarcoptic  mange  may  be  successfully 
treated  by  the  use  of  the  lime  and  sulphur  dip  or  nicotine 
dip,  repeating  every  ten  days  for  three  dippings, 
provided  that  the  quarters  are  cleaned  and  disinfected 
and  the  thick  scabs  are  removed  so  that  the  dipping  solu- 
tion may  gain  access  to  the  parasites.  Some  old  chronic 
cases  do  not  respond  readily,  if  at  all,  to  treatment  because 
of  the  thick,  wrinkled  skin  which  protects  the  parasite. 

Demodectic  Mange 

Demodectic  or  red  mange  is  not  so  prevalent  in  swine 
in  America  as  is  sarcoptic  mange.  Red  mange  rarely 
occurs  enzootically. 

The  cause  of  red  mange  is  the  Demodex  folliculorum, 
var.  suis.  This  parasite  is  not  visible  to  the  unaided  eye. 
Microscopically,  it  is  found  to  be  similar  in  shape  to  an 
oat  grain  and  has  four  pairs  of  short  legs.  The  life  cycle 
of  this  parasite  is  practically  the  same  as  of  the  Sarcoptes 
scarbiei,  var.  suis,  except  that  the  ova  are  deposited  in  a 
pustule  in  the  hair  follicles  and  sebaceous  glands  instead 
of  in  intradermal  galleries. 

Lesions. — The  skin  of  the  legs  of  swine  is  most  fre- 
quently affected.  The  parasite  gains  entrance  to  the 
hair  follicles,  where  it  produces  inflammation  and  causes 
depilation.  The  inflammatory  reaction  causes  a  redness 
of  the  skin,  hence  the  name.  In  a  case  of  long  standing 
the  skin  is  red,  thick,  wrinkled,  cracked,  practically  hair- 
less, and  evolves  a  peculiar  characteristic  odor.  The 
disease  extends  slowly  upon  the  animal  body,  and  it  is 
not  uncommon  to  find  only  one  animal  affected  in  spite 
of  the  fact  that  there  are  many  swine  in  the  same  pen. 
Positive  diagnosis  can  be  made  only  by  identifying  the 
parasite  microscopically. 

Treatment. — This  condition  is  practically  incurable, 
at  least  in  so  far  as  our  present  knowledge  is  concerned. 
Affected  animals   should   be   sent   to   slaughter,   as   this 


158  SWINE  DISEASES 

condition  does  not  impair  tlie  meat  for  food.  If  for  any 
reason  the  animal  is  to  be  kept  upon  the  premises,  it 
should  be  placed  in  rigid  quarantine. 

Tick  Infestation 

Infestation  of  swine  with  ticks,  particularly  the  ear 
ticks  (Ornithodorus  megnini),  has  attracted  the  attention 
of  some  southern  swine  breeders.  These  ticks  locate  in 
the  external  ear  and  produce  irritation  which  annoys  the 
infested  animals.  They  may  be  removed  by  pouring 
into  the  ear  some  alcohol,  dilute  antiseptic  or  bland  oil. 

Thread  Worm  Infestation 

Cutaneous  infestation  by  Filaria  may  occur  in  swine, 
but  it  has  not  l)een  positively  identified. 

Ringworm  Infestation 

Rarely  does  ringworm  occur  in  swine.  The  condition 
is  caused  by  a  Trichophj^ton. 

Lesions. — The  lesions  are  usually  located  on  the  back 
or  the  outer  surface  of  the  thighs  and  are  seen  as  isolated, 
circumscribed,  round,  red  spots  with  a  raised  margin 
which  bears  small  vesicles.  The  central  portion  appears 
normal,  except  that  it  is  scaly.  The  trouble  gradually 
extends  in  all  directions,  the  raised  vesicular  margin 
representing  the  outside  of  the  lesion.  When  the  lesion 
becomes  very  large  the  center,  or  original  lesion,  has 
apparently  recovered.  The  disease  is  transmitted  by 
actual  contact. 

Treatment. — Cleanse  the  affected  parts  and  applj^  a 
five-percent  solution  of  creolin,  repeating  the  treatment 
on  the  fourth  or  fifth  tlav. 


D 


SECTION  VI 
CIRCULATORY  ORGANS 

ISEASES  of  the  circulatory  organs  may  be  of 
common  occurrence  in  swine,  but  such  dis- 
turbances are  rarely  recognized  clinically. 


HEART 
Pericarditis 

Pericarditis,  both  acute  and  chronic,  fibrinous  and 
purulent,  occurs  in  relation  with  hog  cholera,  swine  plague, 
and  erysipelas,  and  more  rarely  as  a  primary  condition. 
The  conditions  have  been  observed  in  autopsies.  The 
acute  type  is  characterized  by  hj'peremia,  hemorrhage, 
and  exudation  upon  the  serous  lining  of  the  pericardium. 
The  serous  surface  of  the  pericardium  will  have  lost  its 
luster  and  the  exudate  may  adhere  to  it  in  shreds.  The 
pericardium  becomes  thickened  in  chronic  pericarditis, 
due  to  the  formation  of  fibrous  tissue. 

Hemorrhage 

Hemorrhages  of  small  size  are  frequently  found  in 
the  heart  muscle.  These  occur  in  infectious  diseases  and 
are  the  result  of  bacterial  emboli  or  injury  of  the  capillaries 
by  chemic  substances  incidental  to  infection.  They  are 
of  significance  to  the  meat  inspector  and  the  diagnostician. 

Subendocardial  hemorrhages  are  common  as  a  sequel 
of  infectious  diseases.  They  are  of  diagnostic  value  and 
are  an  indication  to  the  meat  inspector  of  some  infective 
disease  or  septic  intoxication. 

Fatty  Changes 

Fatty  changes  in  tiie  heart  nuiscle  occur  in  practically 
all  swine  that  have  been  fattened  for  market.  The  fat 
particles  are  found  between  the  muscle  cells  at  first,  but 

159 


160  SWINE  DISEASES 

later  the  cells  become  infiltrated  with  fat.  The  heart  is 
enlarged,  is  paler  in  color,  and  its  density  is  diminished. 
No  visible  symptoms  are  evident,  in  the  majority  of  these 
cases  the  swine  being  excessively  fat  and  refusing  to  move 
about  without  urging.  No  treatment  is  required  unless 
this  condition  arises  in  a  breeding  animal. 

Endocarditis 

Endocarditis  has  been  observed  by  inspectors  and  in 
diagnostic  autopsies,  but  the  disease  is  not  ordinarily 
recognized  by  the  clinician.  The  lesions  found  usually 
consist  of  vegetative  growths  or  denuded  areas  upon  the 
endocardium,  covering  the  valves.  Either  condition  is 
always  associated  with  infection,  and  it  is  not  difficult  to 
demonstrate  bacteria  in  the  lesions. 

Tumors 

Various  tumors  have  been  observed  upon  the  peri- 
cardium and  also  in  the  myocardium.  They  are  of  no 
clinical  significance,  but  are  of  interest  to  inspectors, 
as  the  presence  of  malignant  tumors  is  considered  suffi- 
cient evidence  for  condemnation. 

Parasites 

The  pericardium  rarely  harbors  the  cystic  form  of  the 
Taenia  echinococcus,  but  Cysticerus  cellulosae  is  of  com- 
mon occurrence  in  the  myocardium  of  swine.  The  lesion 
has  the  same  general  appearance  as  it  does  in  voluntary 
striated  muscle.  Sarcosporidiosis  is  not  uncommon  in 
the  heart  muscle  of  swine. 

BLOOD  VESSELS 

Diseases  of  the  blood  vessels  of  swine  have  received 
very  little  consideration,  though  a  few  cases  of  aneurism 
have  been  recorded.  Thrombosis  has  been  observed  in  a 
very  few  instances.  Inflammatory  disturbances  have  not 
been  reported,  or  at  least  the  available  literature  contains 
no  records  of  such  affections.  Phlebitis  has  been  observed 
by  serum  producers.     This  condition  has  occurred  in  the 


CIRCULATORY  ORGANS  161 

ear  veins,  but  has  not  been  of  sufficient  importance  to 
occasion  any  losses. 

BLOOD 

Diseases  of  the  blood  of  swine  have  received  very 
limited  consideration  up  to  the  present  time. 

Anemia 

Werner  reported  his  observation  of  anemia  in  swine 
that  had  been  fed  watery  slop  food,  while  Braasch  ob- 
served anemia  in  suckling  pigs,  but  was  not  successful  in 
identifying  the  cause.  The  usual  lesions  of  anemia  con- 
sist of  lack  of  blood,  paleness  of  the  various  tissues, 
emaciation,  and  a  jelly-like  consistency  of  the  fat.  The 
aflfected  animals  are  depressed,  weak,  and  gradually 
become  emaciated.  Later  edematous  swellings  occur  in 
the  dependent  parts  of  the  body. 

Leukemia 

A  few  cases  of  leukemia  have  been  observed  in  swine 
on  postmortem  examination.  The  exact  cause  of  disease 
is  unknown,  but  it  is  probably  of  an  infectious  origin. 

Lesions. — Porcine  leukemic  cases  thus  far  observed 
are  of  the  lymphatic  type.  The  lymph  glands  become 
enlarged,  due  to  hyperplasia  of  the  lymphoid  tissue,  and 
there  are  frequently  necrotic  centers.  By  scraping  the 
cut  surface  of  a  lymph  gland  a  milk-white  fluid  is  ob- 
tained. The  spleen  contains  leukemic  centers  and  is 
enlarged,  and  the  liver  may  be  similarly  affected. 

Cases  of  leukemia  have  not  been  studied  clinically. 
The  disease  is  chronic  in  nature. 

SPLEEN 

The  spleen  is  subject  to  hemorrhages  and  is  engorged 
in  hog  cholera  and  in  other  septicemic  diseases. 

Necrosis 

Necrosis  of  the  spleen  is  of  common  occurrence  in 
swine  that  have  died  as  a  result  of  injection  of  a  virus 
containing  the  Bacillus  necrophorus.     These  centers  vary 


162  SWINE  DISEASES 

in  size  from  that  of  a  dime  to  a  fifty-cent  piece,  are  grayish - 
white  in  color,  and  usually  have  a  raised  border  and  de- 
pressed center.  There  may  be  only  one  or  two  of  these 
necrotic  foci,  or  the  spleen  may  be  full  of  them. 

Hypertrophy 

Hypertrophy  of  the  spleen  is  rather  common.  The 
condition  occurs  in  leukemia,  tumor  formation,  and  in 
swine  that  are  fed  excessively. 

Tumors 

Sarcomatosis  is  a  relatively  common  condition  in  the 
spleen.  The  majority  of  the  cases  observed  were  primarjs 
but  secondary  splenic  sarcomas  do  occur.  The  tumor  is 
usually  multiple,  the  foci  varying  in  size  from  mere  points 
up  to  masses  as  large  as  a  hen's  egg.  The  centers  are 
white  or  grayish-white  in  color,  and  are  rather  firm. 
They  are  usually  circumscribed  with  a  thin,  fibrous 
capsule. 


SECTION  VII 
THE  NERVOUS  SYSTEM 

DISEASES  of  the  nervous  system  of  the  various 
domesticated  animals  have  not  been  sufficiently 
investigated  for  a  good  description  to  be  given 
of  them.  This  is  particularly  true  in  regard  to  diseases 
of  the  nervous  system  in  swine. 

Malformations  of  the  brain  or  spinal  cord  are  com- 
mon in  swine.  They  are  observed  principally  by  the 
breeder  and  in  small  pigs,  as  the  majority  of  these  mal- 
formations are  of  such  a  nature  that  the  affected  animal 
dies  soon  after  birth.  Cranial  and  spinal  clefts,  with 
associated  hernia  of  the  meninges,  brain,  or  spinal  cord, 
are  the  most  common  deformities. 

Functional  disturbances  of  the  brain,  such  as  delirium, 
are  sometimes  observed,  but  this  condition  is  not  com- 
mon. It  is  usually  the  result  of  organic  disease  of  the 
brain,  although  it  may  be  caused  by  intestinal  parasites. 
The  affected  swine  champ  their  jaws,  grunt,  run  against 
the  fence,  posts,  or  similar  objects,  tremble,  and  may  even 
bite.  ^Yhen  the  cause  is  removed  the  animals  make  a 
speedy  recovery,  although  succeeding  attacks  may  occur. 

Viciousness  is  closely  associated  with  delirium.  This 
condition  is  dependent  upon  the  nature  and  tempera- 
ment of  the  animal  and  is  manifested  by  a  desire  to  attack 
man  or  other  animals.  Vicious  swine  bite,  and  boars  use 
their  tusks  to  inflict  injuries,  and  are  sometimes  successful 
in  disemboweling  their  victim.  Viciousness  is  inherited 
or  acquired,  and  vicious  swine  should  never  be  used  for 
breeding  purposes.  Viciousness  is  acquired  by  swine 
that  are  nervous.  Such  swine  soon  become  irritable, 
then  vicious,  as  a  result  of  teasing  or  brutal  treatment. 
One  instance  is  recalled  of  a  nervous  sow  that  became 
vicious  because  the  owner's  son  irritated  and  tantalized 

163 


164  SWINE  DISEASES 

her  by  catching  her  small  pigs  and,  while  they  were 
squealing,  carried  them  around  the  pen.  The  best 
method  to  pursue  in  cases  of  viciousness  in  swine  is  to 
prepare  them  for  slaughter  and  market  them  as  soon  as 
possible. 

Sunstroke  and  Heat  Stroke 

It  may  be  possible  to  diflferentiate  betw^een  sunstroke 
and  heatstroke  in  man,  and  possibly  also  in  horses,  but 
such  a  distinction  is  scarcely  warranted  in  swine. 

Sunstroke  is  claimed  to  be  due  to  the  action  upon  the 
nerve  cells  of  actinic  rays  of  the  sun,  and  heat  stroke  to 
a  disturbed  equilibrium  of  heat  production  and  heat  dis- 
sipation. The  two  conditions  frequently  occur  simul- 
taneously in  the  same  animal. 

Etiology. — These  conditions  are  the  result  of  direct 
exposure  to  sunshine  and  excessive  heat.  Driving  swine 
in  droves  is  occasionally  accompanied  by  cases  of  heat 
stroke,  and  this  may  also  be  observed  in  carload  lots  in 
which  the  swine  are  crowded  and  the  shipment  made  in 
extremely  hot  weather.  The  same  condition  arises  in 
swine  that  are  hauled  in  wagons,  if  proper  precautions 
are  not  taken.  Lack  of  proper  shade  predisposes  the 
swine  to  sunstroke  and  to  heat  stroke. 

Lesions. — There  are  no  gross  lesions  that  characterize 
either  sunstroke  or  heatstroke,  except  a  parboiled  appear- 
ance of  parenchymatous  tissues.  Microscopically,  the 
nerve  cells  are  found  to  contain  coagula,  and  there  may 
be  cloudy  swelling  of  all  parenchymatous  tissues. 

Symptoms. — Uncertain  gait,  dullness,  depression, 
increased  respiration,  and  anxious  expression  are  the 
principal  symptoms  observed  in  the  early  stages  of  these 
conditions.  The  temperature  may  be  very  high.  Muscu- 
lar tremors,  falling  to  the  ground,  and  convulsions  are  the 
final  symptoms.  The  course  of  the  disease  is  short. 
In  some  instances  the  animal  succumbs  within  a  few 
minutes  after  the  onset;  in  other  cases  the  animal  may 
Jive  for  from  one  to  three  days,  and  in  rare  instances 
may  recover. 


THE  NERVOUS  SYSTEM  165 

Treatment. — Place  the  auimal  in  a  shady  spot, 
give  rapidly  diffiisable  stimulants,  and  apply  cool  but  not 
cold  water  over  the  body,  and,  if  possible,  use  ice  packs 
on  the  head. 

Lightning  Stroke 

Lightning  stroke  sometimes  occurs  in  swine,  par- 
ticularly among  those  in  pasture.  The  lesions  of  light- 
ning stroke  are  not  well  marked.  Burning  of  the  surface 
and  irregular  congested  streaks  may  be  observed.  Tissue 
hemorrhage  may  or  may  not  occur.  The  carcass  of  an 
animal  dead  from  lightning  stroke  putrefies  rapidly. 

Swine  that  are  struck  by  lightning  may  be  instantly 
killed  or  they  may  be  rendered  unconscious  or  only  tem- 
porarily stunned.  Those  that  are  not  killed  will  show 
unsteadiness  of  gait,  and  they  may  even  be  unable  to 
walk.  The  animals  that  are  not  killed  instantly  usually 
make  a  speedy  and  complete  recovery.  Little  is  required 
in  the  way  of  treatment.  The  affected  animals  should 
be  made  comfortable  and,  if  necessary,  stimulants  should 
be  given. 

Epilepsy 

Epilepsy  is  a  nervous  disorder  characterized  by 
sudden  temporary  loss  of  consciousness,  with  partial  or 
general  convulsions.  Swine,  particularly  those  closely 
confined,  are  frequently  affected  with  epilepsy.  This  is 
a  functional  disorder,  the  result  of  a  variety  of  causes, 
parasites,  tumorous  growths,  excitement,  and  fear  being 
among  the  common  causative  factors,  although  in  many 
cases  the  cause  has  not  been  determined. 

Lesions. — The  disease  is  primarily  a  functional  dis- 
order, and  there  are  no  lesions  that  are  constant  and  can 
be  said  to  be  accountable  for  the  seizures  of  epilepsy. 

Symptoms. — The  approach  of  an  attack  is  evidenced 
by  restlessness,  uneasiness,  muscular  tremors,  rolling  of 
the  eyes,  and  champing  of  the  teeth.  These  premoni- 
tory symptoms  are  succeeded  by  falling,  and  extension, 
and  frequent  jerking  of  the  legs  and  head.  The  mouth  is 
usually   open,   and  from   it   saliva  is   discharged   freely. 


166  SWINE  DISEASES 

There  may  also  be  defecation,  urination,  and  discharge 
of  semen.  The  seizures  are  of  short  duration,  rarely 
exceeding  five  minutes.  The  attacks  may  occur  in  rapid 
succession,  or  considerable  time  may  elapse  between 
attacks. 

Treatment. — Treatment  is  of  no  practical  value, 
except  to  remove  the  cause  when  known.  The  affected 
animals  should  be  destroyed  if  the  seizures  are  frequent 
and  severe,  or  in  mild  cases  the  animals  should  be  pre- 
pared for  market.  They  should  never  be  used  for  breed- 
ing, as  apparently  the  condition  is  inherited. 

Dentition  Eclampsia 

A  condition  called  dentition  eclampsia  occurs  in  young 
pigs.  This  is  very  similar  to  epilepsy.  It  is  caused  by 
the  irritation  resulting  from  the  eruption  of  teeth,  and 
future  attacks  are  easily  obviated  by  lancing  the  gums. 

Chorea 

Chorea  is  a  neurotic  condition  characterized  by  rapid 
contractions  of  muscles  or  groups  of  muscles. 

Etiology. — In  many  instances  chorea  appears  to  be 
purely  functional.  Some  have  attributed  it  to  Thrombosis ; 
toxic  substances  may  be  a  factor;  in  producing  it  and  in 
some  cases  malnutrition  predisposes  and  possibly  excites 
the  condition. 

No  constant  tissue  change  has  been  identified  with 
chorea. 

Symptoms. — Twitching  of  muscles  or  groups  of 
nmscles  more  or  less  continuously  except  during  sleep 
characterizes  chorea.  The  disease  may  be  outgrown  in 
the  course  of  cue  or  two  months,  or  it  may  become 
chronic. 

Treatment. — Various  drugs  luiA-e  been  recommended 
to  relieve  this  condition,  but  the  best  plan  is  to  destroy 
pigs  that  have  aggravated  cases,  and  to  fatten  and  market 
those  having  mild  attacks. 


THE  NERVOUS  SYSTEM  167 

Cerebral  Hyperemia 

Hyperemia  no  doubt  occurs  in  the  brain  and  meninges 
of  swine,  but  such  cases  have  received  meager  cHnical 
investigation.  A  few  cases  of  purulent  cerebritis,  or 
staggers,  have  been  observed.  Some  of  these  cases  were 
caused  by  wormeaten,  moldy  corn,  or  at  least  no  new 
cases  appeared  after  changing  the  feed.  The  cerebral 
tissue  was  affected  and  the  lesion  consisted  of  a  liquefying 
necrosis,  the  necrotic  area  usually  occurring  in  relation 
to  the  lateral  ventricle  and  being  unilateral  in  the  cases 
investigated.  The  liquefied  necrotic  tissue  was  grayish 
red  in  color  and  usually  represented  an  area  about  the 
size  of  an  English  walnut.  The  affected  swine  were 
generally  dull  in  the  beginning,  but  in  one  case  observed 
the  animal  was  excitable  and  delirious.  Smne  affected 
with  cerebral  hyperemia  usually  evidence  an  unsteady 
gait  and  may  fall  to  the  ground  and  show  symptoms  of 
convulsions.  One  case  was  observed  that  turned  in  a 
circle,  jumped  up  from  the  ground,  and  performed  other 
antics. 

Treatment. — Treatment  is  of  little  value  after  the 
brain  substance  has  become  necrotic.  In  the  very  early 
stages  drastic  purgatives  may  be  of  value,  particularly  if 
the  cause  lay  in  the  provender. 

Parasites 

Rarely  does  the  Cysticercus  cellulosse  develop  in  the 
brain  of  swine.  The  cyst  does  not  develop  as  readily  in 
the  brain  as  in  a  muscle,  and  it  is  the  exception  to  find 
a  matured  cyst  in  the  nervous  tissue.  The  symptoms 
produced  will  depend  ujjon  the  location  of  the  cyst  in  the 
brain. 


SECTION  VIII 

INFECTIOUS  DISEASES 

HOG  CHOLERA 

HOG  cholera  is  a  specific  septicemic  disease  of 
swine.  It  is  contagious  and  infectious,  and  may 
be  either  acute  or  chronic.  The  disease  is 
characterized  by  tissue  hemorrhages  and  comphcations 
of  the  intestinal  mucosa  and,  less  frequently,  by  hemor- 
rhages of  the  lungs. 

Geographical  distribution. — The  first  identified 
outbreak  of  hog  cholera  in  the  United  States  occurred  in 
Ohio  in  1833.  From  this  original  center  it  has  spread 
widely  and  now  prevails  more  or  less  continuously  in 
every  state  of  the  Union  as  well  as  in  the  surrounding 
countries,  including  the  island  possessions  of  the  United 
States.  The  disease  was  positively  recognized  in  England 
in  1826,  and  it  still  prevails  there.  In  1896  approximately 
one  third  of  the  swine  population  of  England  died  of 
cholera.  The  disease  was  introduced  into  Denmark  in 
1887,  and  spread  into  Sweden  the  same  year.  It  also 
appeared  in  France  in  1887.  Hog  cholera,  or  a  very 
similar  disease,  appeared  in  Germany  in  1866,  Prussia, 
Austria,  and  Hungary  were  invaded  in  1895.  From  all 
reports,  it  is  apparent  that  hog  cholera  prevails  in  prac- 
tically every  country  in  which  swine  are  maintained. 

Hog  cholera  was  first  investigated  systematically  in 
America  in  1885,  under  the  directions  of  Salmon.  The 
disease  was  thought,  and  apparently  proved  at  that  time, 
to  be  due  to  a  short,  rod-shaped  bacteria. 

De  Schweinitz  and  Dorset  further  investigated  the 
disease  in  1903,  and  the  Bureau  of  Animal  Industry  have 
continued  their  investigations  up  to  the  present  time. 

Extent. — Information  obtained  from  various  sources 
indicates  that  hog  cholera  has  been  prevalent  in  America 

169 


170  SWINE  DISEASES 

for  the  past  thirty  or  forty  years.  The  average  annual 
loss  in  the  United  States  for  the  past  four  decades  prob- 
ably exceeds  $50,000,000  annually,  and  in  1897  the  losses 
due  to  this  disease  alone  approximated  $100,000,000. 
During  the  years  1912-13  a  severe  epizootic  of  hog 
cholera  extended  throughout  the  principal  hog-raising 
section  of  the  United  States,  the  loss  being  excessive  and 
for  the  country  at  large  amounting  to  over  $100,000,000 
each  year.  In  1913  there  were  61,178,000  swine  in  the 
United  States,  of  which  ten  to  fifteen  percent  died  of 
cholera.  The  losses  from  hog  cholera  in  1912  in  Iowa, 
Nebraska,  Kansas,  and  Missouri  exceeded  3,000,000 
hogs  valued  at  $30,000,000.  The  losses  in  Iowa  alone  for 
the  years  1911-14  have  exceeded  $10,000,000  annually. 

Hog  cholera  is  no  doubt  the  most  surely  fatal  disease 
of  swine  in  America,  and  at  this  time  it  is  the  most  im- 
portant disease  economically  in  the  United  States. 

Etiology.— The  cause  of  hog  cholera  is  attributed  to 
a  filterable  virus.  The  relation  of  a  filterable  virus  to 
hog  cholera  was  first  recognized  by  De  Schweinitz  and 
Dorset  in  1904,  and  similar  investigations  by  Boxymeyer 
of  Michigan  were  also  concluded  in  1904.  Other  inves- 
tigators have  verified  the  findings  by  De  Schweinitz  and 
Dorset.  The  virus  of  hog  cholera  occurs  in  the  blood  and 
therefore  in  practically  all  the  tissues  of  the  body  of  an 
infected  swine.  One  to  two  cubic  centimeters  of  filtered 
blood  serum  from  swine  affected  with  hog  cholera  will 
produce  typical  symptoms  of  this  disease  when  injected 
subcutaneously,  intramuscularly,  intraperitoneally,  or 
intravenously  into  a  healthy,  susceptible  pig.  The 
symptoms  become  evident  in  from  five  to  seven  days  after 
the  inoculation. 

The  virus  has  not  yet  been  successfully  cultivated,  but 
very  recent  discoveries  indicate  that  in  the  near  future 
the  cultivation  of  it  may  become  practicable  in  the  pro- 
duction of  virus  for  the  purpose  of  hyperimmunization  of 
swine  for  the  production  of  anti-hog-choleru  serum. 

Hog-cholera  virus  is  ullramicroscopic  and  passes 
through  porcelain  filters.     The  virus  retains  its  virulence 


INFECTIOUS  DISEASES  171 

in  fluids  at  room  temperature  for  from  two  to  three 
months,  but  is  destroyed  by  heating  to  seventy  degrees 
Centigrade  for  one  hour.  When  dried  it  becomes  more 
resistant  to  the  influence  of  high  temperature.  At  the 
temperature  of  an  ice  box  the  virulence  of  the  virus  is 
retained  for  many  months.  It  is  very  resistant  to  dilute 
solutions  of  phenol,  corrosive  sublimate,  and  chinosol. 
The  length  of  time  that  virus  may  remain  virulent  on 
infected  premises  has  not  yet  been  determined,  but  it 
easily  survives  a  single  winter. 

In  addition  to  the  filterable  virus,  certain  bacteria, 
including  one  Spirillum,  may  be  factors  in  the  causation 
of  hog  cholera. 

The  Bacillus  suipestifer  is  no  doubt  a  factor  in  the 
production  of  secondary  lesions  and  of  some  of  the  compli- 
cations of  hog  cholera,  and  from  the  original  investigations 
under  the  direction  of  Salmon  and  some  recent  experiments 
it  seems  probable  that  an  occasional  outbreak  of  a  disease 
very  similar  symptomatically  and  anatomically  to  cholera 
is  caused  by  the  Bacillus  suipestifer.  In  fact,  the  intra- 
venous injections  of  the  Bacillus  suipestifer  that  have  been 
recently  isolated  produce  a  septicemic  disease  that  termi- 
nates fatally  in  from  one  to  three  days.  It  has  been 
suggested  that  the  disease  produced  by  the  Bacillus 
suipestifer  be  designated  para-cholera. 

The  Bacillus  suipestifer  is  a  short,  motile,  rod-shaped 
bacteria.  It  forms  no  spores,  or  at  least  none  have  been 
demonstrated.  This  organism  grows  aerobically  and 
anaerobically  on  practically  all  artificial  media.  It  will 
withstand  ordinary  dessiccation  for  four  months  or  even 
longer,  but  sunlight  destroys  it  when  exposed  only  a  few 
minutes.  This  organism  produces  an  acute  or  chronic 
inflammation,  and  necrosis  of  the  intestinal  mucosa  and 
the  mesenteric  lymph  glands.  If  the  animals  are  previ- 
ously starv^ed  and  the  acid  reaction  of  the  gastric  juice 
neutralized  before  feeding  the  cultures  of  Bacillus  suipes- 
tifer, they  will  contract  an  acute  disease,  with  symptoms 
similar  to  those  of  septicemia,  and  usually  die  on  the 
third  day.     Intravenous  injections  of  the  cultures  pro- 


172  SWINE  DISEASES 

duce  septicemia,  resulting  in  death  in  from  one  to  three 
days.  The  infection  with  suipestifer  is  not  transmissible 
from  swine  to  swine,  and  swine  that  have  recovered  from 
the  effects  of  infection  with  the  Bacillus  suipestifer  are 
still  susceptible  to  the  filterable  virus. 

Bacillus  suisepticus  is  frequently  demonstrable  in  the 
carcasses  of  swine  that  have  died  of  hog  cholera.  This 
organism  is  the  causative  agent  of  swine  plague,  and  will 
receive  proper  consideration  in  the  discussion  of  that 
disease.  Suffice  to  say  at  this  place,  it  is  frequently  an 
associated  infection  with  the  filterable  virus,  the  disease 
resulting  being  a  mixed  infection  of  hog  cholera  and  swine 
plague. 

Spirochseta  suis  has  been  investigated  by  King  and 
Hoffmann.  The  following  are  the  conclusions  of  a  report 
on  it:  "Its  Significance  as  a  Pathogenic  Organism,"  that 
was  published  in  Vol.  13,  No.  12,  of  the  Journal  of  Infec- 
tious Diseases: 

"Spirochaeta  suis  is  an  organism  found  in  the  intestinal  ulcers, 
crypts  in  the  ceca,  and  external  local  lesions  of  animals  suffering  from 
hog  cholera.  It  is  a  typical  spirochete,  simulating  in  many  characteristics 
Spirochseta  pallida,  Spirochaeta  gallinarum,  and  other  forms  whose 
morphology  and  life  history  are  becoming  better  understood.  Spiroch- 
aeta suis  appears  to  be  capable  of  breaking  up  into  granules,  and  these 
granules  may  play  an  important  part  in  the  life  cycle  and  physiological 
functions  of  the  organism.  They  are  present  in  the  blood  of  cholera 
hogs,  in  cultures  of  the  Spirochaeta  suis,  and  are  capable  of  producing 
the  disease  in  healthy  hogs.  " 

"In  the  blood  of  hogs  suffering  from  cholera  the  presence  of  a  rela- 
tively large  spirochete  in  a  few  numbers  has  been  recognized.  As 
this  organism  has  not  been  found  in  the  blood  of  normal  hogs  it  may 
represent  Spirochaeta  suis  in  a  transitional  form.  Its  morphological 
variation  from  Spirochaeta  suis,  as  found  in  ulcers  and  local  foci,  maj' 
be  due  to  the  unfavorable  action  of  blood  as  a  medium  or  to  its  natural 
processes  as  a  part  of  the  life  cycle  of  the  species. 

"Spirochaeta  suis  is  an  obligatory  anaerobic  organism  and  usually 
requires  several  weeks'  incubation  for  growth  to  take  place  on  artificial 
culture  medium.  It  may  be  transferred  from  generation  to  generation 
on  artificial  culture  medium.  Cultures  containing  the  organism  in 
the  form  of  granules  and  spirochetes  may  be  passed  through  bacteria- 
proof  filters  and  the  spirochetes  removed,  the  few  small  granules  which 
pass  through  being  capable  of  producing  hog  cholera  or  resistance  to 
the  disease. 

"Spirochffita  suis  is  capable  of  producing  typical  hog  cholera  when 
injected  into  healthy  hogs.  This  is  true  not  alone  of  contaminated 
cultures  made  directly  from  the  intestinal  ulcers  of  cholera  hogs;  second 
and  third  generations  on  artificial  culture  media,  containing  the  Spiro- 


INFECTIOUS  DISEASES  173 

clia;ta  suis,  as  well  as  the  Berkefeld  filtrates  of  the  same  transfers,  are 
capable  of  producing  hog  cholera  and  marked  reactions,  which  confer 
more  or  less  protection  against  the  disease.  The  pathogenicity  of  these 
cultures  does  not  appear  to  be  due  to  the  passage  of  an  unknown  'invisible 
microorganism'  which  is  finally  transmitted  to  healthy  hogs  by  inocu- 
lation. Control  experiments  tend  to  show  that  the  pathogenicity  of 
the  cultures  of  Spirochaeta  suis  is  due  to  the  species  itself  in  the  form  of 
spirochetes  or  granules. 

"Finally,  in  those  hogs  which  receive  the  disease  from  cultures  of 
Spirochaeta  suis,  the  organism  is  present  in  the  intestinal  lesions  or 
local  external  lesions,  as  demonstrated  by  the  dark-field  examination. 

"From  the  above  results,  which  have  practically  fulfilled  Koch's 
laws,  in  so  far  as  it  is  possible  with  an  organism  possessing  the  biological 
characteristics  of  spirochetes,  it  may  logically  be  concluded  that  Spiro- 
chaeta suis  is  more  nearly  established  as  the  specific  cause  of  hog  cholera 
than  any  other  known  organism." 

From  the  foregoing  it  will  be  noted  that  there  is  still 
some  contention  as  to  the  cause  of  hog  cholera.  At  this 
time  the  filterable  virus  is  usually  given  as  the  cause,  but 
future  investigations  may  reveal  faulty  technic  or  errone- 
ous conclusions  of  the  experiments  that  have  been  con- 
ducted and  establish  a  new  causative  factor  of  hog 
cholera. 

Source  of  Infection. — The  original  source  of  the 
virus  of  hog  cholera,  like  the  origin  of  other  viruses  and 
pathogenic  agents,  is  unknown.  The  following  are  the 
principal  sources  of  virus  of  hog  cholera:  infected  swine, 
the  discharges  from  infected  swine,  the  carcasses  of  swine 
dead  of  cholera,  virus  used  in  simultaneous  immunization; 
food,  water,  veliicles  of  transportation,  stock  yards,  and 
any  other  substance  or  objects  contaminated  with  the 
discharges  of  infected  swine,  or  the  tissue  juices  or  prod- 
ucts of  the  carcasses  of  swine  dead  of  cholera. 

From  the  foregoing  the  ease  of  obtaining  infection  is 
readily  comprehended.  The  virus  is  transmitted  from  an 
infected  swine  on  noninfected  premises  to  other  sw^ne,  or 
to  soil,  food,  water,  bedding,  and  general  surroundings, 
thus  practically  insuring  infection  of  other  swine  on  the 
same  premises  and  other  premises  as  w^ell.  Serious  out- 
breaks of  cholera  are  sometimes  traceable  to  the  intro- 
duction of  a  new  boar,  or  other  animal,  that  is  infected. 

If  the  carcass  of  a  swine  dead  of  cholera  is  permitted 
to  remain  in  the  hog  lot,  other  swine  will  become  infected 


174  SWINE  DISEASES 

by  eating  of  the  flesh,  and  the  soil  and  surroundings  will 
be  contaminated  with  the  virus.  Some  men  have  shown 
their  faith  in  the  protection  of  swine  against  cholera  with 
serum  by  putting  the  carcass  of  a  swine  dead  of  cholera  in 
their  pens  and  thus  infecting  their  premises. 

From  the  lack  of  care  in  the  use  of  virus  in  producing 
a  permanent  immunity  there  is  little  doubt  but  that  hun- 
dreds of  farms  have  become  infected.  Food  hauled  in 
wagons  or  other  vehicles  that  have  been  previously  used 
in  transporting  cholera-infected  swine  may  become 
contaminated  and  infect  healthy,  susceptible  swine  and 
thus  produce  hog  cholera.  Water,  too,  is  frequently  the 
source  of  infection.  This  is  especially  noticeable  in  the 
spread  of  hog  cholera  in  sections  of  country  in  which  there 
are  many  small  streams.  Such  enzootics  usually  follow 
the  streams.  The  contamination  of  surface  water  is  due 
to  the  discharges,  and  even  to  the  carcasses  of  cholera- 
infected  hogs  being  washed  by  rain  water  into  the  small 
streams.  Many  hog  raisers  have  fenced  and  made 
pastures  of  the  low  lands  and  the  small  streams  of  water, 
thus  favoring  the  introduction  of  infection  into  their 
herds. 

Almost  every  state  in  the  Union,  and  many  foreign 
countries,  permit  the  shipment  of  cholera-infected  swine  to 
mai'ket  centers.  By  this  means  stock  yards,  stock  cars, 
and  the  railroad  right  of  way  become  contaminated  with 
the  discharges  of  cholera-infected  swine,  and  the  chances 
are. that  some  of  the  discharges  contain  the  virus  of  hog 
cholera  in  a  sufficiently  virulent  form  to  produce  cholera 
in  healthy,  susceptible  swine.  By  this  means  cholera  is, 
no  doubt,  frequently  transported  hundreds  of  miles,  and 
new  centers  produced.  As  yet  few  if  any  states  actually 
require  the  cleaning  and  disinfecting  of  cars  that  are 
known  to  have  been  used  to  transport  cholera-infected 
hogs  to  market,  and  therefore  the  cars  continue  as  a 
source  of  infection  for  some  time  after  the  cholera- 
infected  hogs  luive  been  unloaded.  By  the  practice  of 
shipping  cholera  hogs  to  market,  practically  all  public 
stock  yards  become  infected  and  are  therefore  a  source  of 


INFECTIOUS  DISEASES  175 

danger  in  the  community.  The  cholera-infected  swine 
are  hauled  or  driven  from  the  farm  to  the  railroad  station 
along  or  over  the  public  road,  which  thus  becomes  a 
source  of  infection,  the  virus  of  which  may  collect  on  the 
feet  of  horses,  on  the  wheels  of  w^agons  or  other  vehicles, 
and  be  transported  to  farms  where  infection  had  not 
before  been  present. 

The  possibility  of  virus  carriers  of  hog-cholera  infec- 
tion must  be  admitted,  for  such  carriers  and  distributers  of 
infection  are  recognized  in  other  infective  diseases.  It 
has  been  claimed  by  good  authorities  that  swine  ihimun- 
ized  simultaneously  do  not  eliminate  the  virus,  but  this 
claim  has  not  been  satisfactorily  proved,  and  because  of 
the  possibility  of  such  swine  eliminating  infection,  they 
must  be  considered  a  source  of  infection. 

Dogs,  crows,  buzzards,  and  pigeons  are  scavengers,  and 
are  an  important  factor  in  the  dissemination  of  infection. 
Neighbors  visiting  back  and  forth  and  exchanging  labor 
are  prolific  means  of  carrying  infection  from  place  to 
place.  And  careless  veterinarians  have  in  some  instances 
apparently  been  responsible  for  the  transmission  of  hog 
cholera  from  infected  to  non-infected  premises. 

Manner  of  infection. — Hog  cholera  may  be  trans- 
mitted by  direct  or  indirect  infection.  Direct  infection 
may  be  affected  by  the  actual  contact  of  a  healthy, 
susceptible  swine  with  one  affected  with  cholera.  Direct 
infection  may  also  occur  in  idero,  the  pigs  becoming 
infected  before  birth.  This  statement  may  be  questioned 
by  some,  but  the  fact  that  pregnant  sows  abort  when  they 
become  affected  with  hog  cholera  is  common  knowledge 
among  swine  breeders.  It  has  also  been  observed  that 
abortion  is  of  frequent  occurrence  in  pregnant  sows  that 
are  simultaneously  immunized.  The  transmission  of  the 
virus  from  the  sow  to  the  pig  in  utero  would  not  seem 
difficult  when  it  is  remembered  that  this  virus  readily 
passes  through  porcelain  filters. 

Indirect  infection  also  is  of  common  occurrence  in 
hog  cholera.  This  is  accomplished  by  the  infection  being 
introduced  on  food  stuff,  in  water,  in  the  inspired  air,  or 


176  SWINE  DISEASES 

on  foreign  bodies,  such  as  splinters  or  stubble.  Indirect 
infection  is  the  manner  of  infection  that  occurs  when  new 
centers  are  established  without  the  introduction  of  a 
diseased  animal. 

Susceptibility. — Young  swine  are  apparently  most 
susceptible  to  cholera  immediately  after  weaning.  How- 
ever, swine  of  all  ages  may  become  affected.  Thus 
sucking  pigs  or  old  brood  sows  or  boars  may  contract 
cholera  and  die  of  its  effects. 

Channels  of  entrance  of  the  inf  ection.^ — The  virus 
of  hog  cholera  most  frequently  gains  entrance  to  the  body 
of  the  swine  by  way  of  the  digestive  tube,  upon  contami- 
nated food  or  water,  or  in  various  substances  that  swine 
are  likely  to  chew  or  ingest.  Infection  may  also  be 
introduced  through  the  respiratory  tract,  but  infection 
by  this  avenue  of  entrance  is  not  common.  The  virus 
may  be  introduced  through  the  skin  by  means  of  barbs, 
awns,  splinters,  or  similar  objects,  but  this  avenue  of 
entrance  is  not  common  in  natural  infection. 

In  the  production  of  a  permanent  immunity  by  the 
use  of  the  virus  and  serum,  the  virus  is  introduced  through 
the  skin  by  a  hypodermic  syringe.  Injection  for  the 
purpose  of  hyperimmunizing,  in  the  production  of  anti- 
hog-cholera  serum,  is  done  intravenously  in  an  ear  vein. 
Infection  can  be  successfully  accomplished  by  intraperi- 
toneal or  intramuscular  injections  of  the  virus,  but  natu- 
ral infection  rarely  occurs  in  this  way. 

Period  of  incubation. — The  period  of  incubation 
after  natural  infection  is  variable,  depending  upon  the 
virulency  of  the  virus  and  the  resistance  of  the  infected 
swine.  In  most  instances  there  will  be  a  rise  of  tem- 
perature from  the  fifth  to  the  seventh  day,  and  the 
animals  will  be  visibly  sick  by  the  tenth  day  after  infec- 
tion. The  period  of  incubation  in  inoculation  experi- 
ments varies  from  four  to  seven  days. 

Lesions. ^ — The  anatomical  changes  observed  in  hog 
cholera  are  quite  variable  because  of  the  multiform  types 
that  it  assumes,  probably  due  to  complications.  The 
following  types  have  been  described:    pure  hog  cholera 


INFECTIOUS  DISEASES 


177 


or  septicemic  form,  intestinal  form,  pectoral  form,  and 
mixed  form.  The  first-named  is  uncomplicated  hog 
cholera;  the  other  forms  are  due  to  complications. 

Septicemic  form. — In  the  very  acute  cases  no  gross 
lesions  are  evident  except  cloudy  swelling  of  the  paren- 
chymatous organs  indicating  a  high  antemortem  tem- 
perature. In  the  ordinary  acute  cases  the  lesions  corre- 
spond to  those  of  septicemia  and  consist  of  hemorrhages 


Fig:.    11.— MUCOUS    ME^IBRANE   OF    THE   BLADDER. 

\.   Normal.     B.    showing:   inflaniniation    tlue   to   hog:   cholera. 

in  the  serous  membranes,  in  the  mucous  membrane  of  the 
epiglottis,  trachea,  lung,  pharynx,  and  usually  in  the 
spleen  and  kidneys.  The  lymph  glands  are  hyperemic 
and  the  lung  usually  contains  small  areas  of  croupous 
pneumonia  in  the  cardiac  lobe.  The  skin  may  be  hy- 
peremic, and  there  may  be  subcutaneous  hemorrhages. 
The  bone  marrow  is  usually  dark  red  or  black. 

Intestinal  form. — This  type  is  apparently  a  complica- 
tion due  to  the  simultaneous  activity  of  the  filterable 
virus  and  the  Bacillus  suipestifer,  Bacillus  necrophorous. 


178  SWINE  DISEASES 

Bacillus  coli  communis,  Spirochaeta  suis,  or  some  other 
intestinal  infection.  This  type  of  hog  cholera  is  charac- 
terized by  the  general  lesions  of  the  less  acute  septicemic 
type  plus  intestinal  lesions  which  are  as  follows.  The 
lymphoid  tissue  of  the  mucosa  of  the  cecum,  colon,  and 
to  a  less  extent  in  the  ileum,  becomes  tumefied  and  later 
undergoes  necrosis.  The  necrotic  tissue,  remaining  ad- 
herent as  a  dirty  brown  mass,  has  raised  margins  and 
represents  the  so-called  hog-cholera  ulcer.  These  necrotic 
areas  may  be  mere  points  or  they  may  be  as  large  as  a 
silver  dollar  or  even  larger.  In  exceptional  cases  the 
necrosis  may  extend  through  the  intestinal  wall  and 
result  in  fatal  peritonitis  or  intestinal  adhesions.  In  the 
chronic  intestinal  type  there  is  intestinal  adhesions,  in- 
volving especially  the  large  intestine,  although  the  small 
intestines  may  also  evidence  the  same  lesions.  There 
may  be  a  general  diffuse  diphtheritic  inflammation  of  the 
mucosa  of  the  intestine  and  stomach,  the  exudate  cover- 
ing practically  the  entire  surface  of  the  mucous  membrane 
of  the  intestine.  This  organized  exudate  may  become 
dry  or  it  may  become  softened  and  mushlike,  the  color 
of  the  exudate  changing  from  dirty  brown  to  a  yellow  or 
greenish  yellow. 

In  chronic  cases  the  septicemic  lesions  become  modi- 
fied. The  hemorrhages  become  pigmented  areas;  the 
lymph  nodules  become  hyperplastic  and  frequently  necro- 
tic. The  spleen  may  or  may  not  become  extensively 
enlarged  and  necrotic,  the  skin  frequently  becomes  necro- 
tic and  variable  sized  areas  slough,  and  the  ears  become 
tumefied  and  frequently  necrotic,  and  slough.  Tume- 
faction and  necrosis  may  also  occur  in  the  bladder,  mouth, 
pharynx,  and  in  other  regions. 

The  evidence  of  a  previous  attack  of  this  type  of  hog 
cholera  consists  of  granulation  of  the  erosions  of  the 
mucous  membrane  of  the  intestine,  stomach,  mouth,  and 
elsewhere,  and  also  of  granulations  of  the  skin  erosions. 
In  other  cases  there  may  be  scars  and  an  irregular  lumen 
of  the  intestine  due  to  irregular  cicatrization.  The  lymph 
nodes  will  contain  caseous  necrotic  centers. 


INFECTIOUS  DISEASES 


179 


Pectoral  form. — This  type  consists  of  the  hemorrhagic 
form  in  varying  degrees  of  intensity  and  pulmonary 
lesions  which  may  or  may  not  be  associated  with  pleurisy. 
As  previously  stated,  croupous  pneumonia  commonly 
occurs  in  the  septicemic  form,  but  it  is  more  extensive  in 
the  pectoral  form. 


Fig.   13.— MUCOUS   MK.MBRANE  OF  THE  INTESTINE. 

A.    Normal.     B.    showinif    effect    of   cltronic    iiiflaniniation    due    to    hog 
cholera.     V.  typical   hog:   cholera  ulcers. 


The  usual  pulmonary  lesion  consists  of  croupous  pneu- 
monia involving  especially  the  cardiac  lobe  of  the  lung. 
The  appearance  of  the  lung  will  depend  upon  the  stage  of 
pneumonia  existing  at  the  time  of  death  of  the  animal. 
The  affected  portion  may  be  in  the  congestive,  red,  or 
gray  hepatization  or  resolution  stage,  and  occasionally 
there    may    be    abscess    formation    or    necrosis.     More 


180  SWINE  DISEASES 

rarely  will  there  be  evidence  of  catarrhal  pneumonia, 
except  in  those  cases  of  the  simultaneous  occurrence  of 
hog  cholera  and  swine  plague.  The  lesions  of  simple 
catarrhal  pneumonia  occur  in  the  lower  portions  of  the 
lung,  and  are  the  same  when  it  occurs  as  a  complication 
of  hog  cholera  as  in  the  primary  affection  of  catarrhal 
pneumonia  which  has  been  previously  described  (p.  88). 

Pleurisy  may  accompany  the  pneumonic  form  of  hog 
cholera,  but  it  is  exceptional  to  observe  such  cases.  The 
pleurisy  may  be  serous,  fibrinous,  or  hemorrhagic,  and 
in  exceptional  cases  it  may  become  purulent  or  septic. 

Although  subepicardial  and  subendocardial  hemor- 
rhages are  typical  of  the  pure,  uncomplicated  hog  cholera, 
these  lesions  are  more  extensive  in  the  pectoral  form  of 
the  disease. 

Mixed  form. — The  mixed  form  of  hog  cholera  consists 
of  the  septicemic  form  plus  complications  of  the  intestinal 
and  pectoral  forms.  This  form  of  hog  cholera  is  prob- 
ably more  prevalent  than  any  other  type  described,  and 
this  fact  accounts  for  the  difficulty  that  is  frequently 
encountered  in  making  a  diagnosis. 

All  of  the  different  forms  of  hog  cholera  described  are 
frequently  found  in  one  herd  of  hogs.  Occasionally  pecu- 
liar combinations  of  lesions  are  observed,  and  in  some 
instances  it  is  not  possible  to  make  a  diagnosis  until 
several  autopsies  have  been  performed.  In  one  instance 
four  hogs  were  autopsied  and  hemorrhagic  gastritis  was 
the  only  lesion  found.  Two  days  later  another  hog  was 
autopsied,  and  revealed  typical  lesions  of  hog  cholera. 

Symptoms. — Symptoms  of  hog-cholera  are  as  varia- 
ble as  the  lesions.  For  convenience  in  describing  the 
symptoms  will  be  considered  in  four  groups  corresponding 
to  the  four  types  mentioned  in  the  consideration  of 
lesions. 

Septicemic  for  iH. — The  most  acute  or  so-called  peracute 
cases  are  frequently  found  dead,  having  evidenced  no 
symptoms.  The  ordinary  acute  cases  evidence  the  fol- 
lowing symptoms,  usually  in  the  order  mentioned.  The 
affected  animals  are  inclined   to  isolate  themselves  and 


INFECTIOUS  DISEASES 


181 


stand  A\'itli  back  arched  and  bead  hanging,  or  they  may 
crawl  under  the  bedding.  The  appetite  is  at  first  im- 
paired, later  the  animals  refuse  all  food.  In  the  early 
stages  vomiting  may  be  observed.  There  is  usually  con- 
stipation   in    the    beginning,    but    this   is    succeeded   by 


Fig.    13.— HEARTS. 
A.    Showing   acute   inflanimation    of   the   auricle   and    hypereniic    areas 
in   the   ventrical,   a  common   condition   in  hog:   cholera.     B.   normal. 


diarrhea,  the  intestinal  discharges  being  admixed  viiih 
blood.  There  is  usually  a  purulent  conjuncti\-itis;  the 
discharges  accumulate  on  the  eyelashes  and  frequently 
cause  adhesion  of  the  eyelids.  There  may  be  a  limited 
mucopurulent  discharge  from  the  nose.  On  the  second 
or  third  day  erythema  of  the  skin  usually  becomes  evi- 


182  SWINE  DISEASES 

dent,  the  discolored  areas  being  observed  on  the  venter 
surface  inside  the  thighs,  and  are  red  or  reddish  purple  in 
color.  The  ears  become  tumefied  due  to  congestion  and 
edema.  There  is  a  rise  of  temperature,  the  high  tem- 
perature ranging  from  105  to  107  degrees  Fahrenheit,  or 
even  higher,  persisting  throughout  the  acute  attack. 
The  affected  animals  become  weak  as  the  disease  pro- 
gresses, and  it  usually  terminates  fatally  in  from  two  to 
seven  days.  In  some  instances  the  first  manifestation  of 
the  disease  consists  of  rheumatoid  symptoms,  the  disease 
sometimes  being  diagnosed  as  rheumatism. 

Intestinal  form. — The  intestinal  form  of  hog  cholera 
is  manifested  by  symptoms  similar  to  those  described  in 
the  septicemic  form  but  less  intense.  This  form  of  the 
disease  is  less  acute  and  runs  a  longer  course.  Symptoms 
of  digestive  derangements  are  the  principal  evidence  of 
the  disease  and  consist  of  impaired  appetite,  inappetence, 
vomition,  constipation  alternated  Avith  diarrhea,  weak- 
ness, and  rapid  emaciation.  Purulent  conjunctivitis  is 
usually  present.  A  bad  odor  emanates  from  the  mouth 
and  on  inspection  putrefying  accumulated  inflammatory 
exudate  is  observed  adhering  to  the  buccal  mucous  mem- 
brane. The  tonsils  and  pharyngeal  mucous  membrane 
may  be  hyperemic  and  hemorrhagic.  Erythema  of  the 
ventral  surface  may  exist,  the  ears  become  tumefied,  and 
occasionally  necrosis  succeeded  by  sloughing  occurs. 
Areas  of  skin  on  the  back  or  croup  may  become  necrotic 
and  slough,  leaving  large,  deep,  ugly  wounds. 

The  course  of  the  disease  varies  from  two  to  four 
weeks,  the  majority  of  the  affected  animals  succumbing, 
but  occasionally  one  or  more  recover  after  a  long  period 
of  convalescence  in  which  the  diarrhea  is  gradually  over- 
come. There  is  desire  for  food,  and  ultimately  there  is 
a  normal  appetite  and  the  animal  gradually  becomes 
stronger  and  finally  recovers. 

Pectoral  form. — The  symptoms  of  the  pectoral  form 
of  hog  cholera  consist  of  the  symptoms  of  the  septicemic 
form  of  cholera  and  of  pneumonia.  The  symptoms  of  the 
septicemic  type  are  usually  evident  when  the  pneumonia 


PLATE  I. 


Fig.  1 


/ 


t 


/^, 


^■"^I'V 


Fig.  2 


y 


» •ci***!^     ♦  I 


Fig.  1.  Normal  skin  and  skin  showing  red  blotches 
characteristic  of  hog  cholera. 

Fig.  2.  Serous  surface  of  intestine,  showing  sharply 
outlined  petechial  hemorrhages,  due  to  hog  cholera. 


INFECTIOUS  DISEASES 


183 


begins.  The  affected  animals  show  disturbance  of  respi- 
ration by  coughing,  dyspnea,  and  more  or  less  nasal  dis- 
charge, the  intensity  of  the  pneumonic  symptoms  depend- 
ing upon  the  extent  of  lung  involved  in  the  pneumonic 
process.  The  physical  examination  of  the  lung  is  prac- 
tically impossible  because  of  the  thick  chest  wall,  and  the 
respiratory  sounds  and  solidity  of  the  lung  can  be  a  matter 


Fig.   14.— HOG   CHOLERA,    (Early   Stage). 

of  conjecture  only  with  the  clinician.  Conjunctivitis  is 
usually  prominent  in  the  pectoral  form  of  cholera.  Ery- 
thema, tumefaction,  and  necrosis  of  the  ear  and  other  skin 
surfaces  are  not  so  common  in  the  pectoral  as  in  the  intesti- 
nal form  of  the  disease.  Some  digestive  derangements 
are  always  present,  but  they  are  less  intensive  than  in 
the  intestinal  form.  A  high  temperature  prevails  in  the 
pectoral  form,  and  as  a  rule  it  will  average  from  one  to 
two  degrees  Fahrenheit  higher  than  in  the  intestinal  form. 


184  SWINE  DISEASES 

The  course  of  the  pectoral  form  of  cholera  varies  from 
one  to  three  weeks.  The  disease  frequently  terminates 
fatally  within  one  week,  especially  when  there  is  extensive 
lung  involvement.  A  few^  cases  may  assume  a  chronic 
form  and  ultimately  recover. 

Mixed  form. — This  is  the  usual  form  of  cholera,  and 
the  symptoms  evidenced  will  depend  upon  the  complica- 
tions. There  will  be  symptoms  of  digestive  derange- 
ments, such  as  inappetence,  vomition,  constipation,  and 
purgation;  of  pneumonia,  such  as  cough,  dyspnea,  and 
nasal  discharge;  conjunctivitis  and  cutaneous  erythema, 
tumefactions,  and  necrosis,  the  intensity  of  these  various 
symptoms  depending  upon  the  proportionate  involve- 
ment of  the  various  groups  of  organs.  In  addition  there 
will  be  more  or  less  of  the  symptoms  of  the  septicemic 
form  of  cholera,  such  as  reluctance  to  move,  depressed 
head,  arched  back,  and  high  temperature.  In  the  acute 
form  of  the  mixed  type  of  cholera  the  course  is  of  brief 
duration,  terminating  fatally  in  from  one  to  three  days 
after  the  first  symptoms  become  evident.  i-; 

Diagnosis. — From  the  foregoing  description  of  lesions 
and  symptoms  it  is  very  evident  that  the  diagnosis  of 
cholera  is  rather  difficult.  There  are  some  laymen,  and  an 
occasional  veterinarian,  who  diagnose  as  hog  cholera 
practically  all  diseased  conditions  of  swine.  Much  has 
been  written  during  the  last  few  years  concerning  the  diag- 
nosis and  treatment  of  cholera,  but  the  bulk  of  this  lit- 
erature has  come  from  serum  producers,  and  some  of  it 
has  apparently  been  written  without  suflScient  investiga- 
tion to  justify  the  conclusions. 

The  symptoms  evidenced  may  cause  a  clinician  to 
suspect  cholera,  but  the  diagnosis  should  not  be  based 
upon  symptoms  alone.  Lesions  observed  in  autopsy  may 
or  may  not  be  sufficiently  characteristic  for  one  to  arrive 
at  a  positive  diagnosis  of  cholera.  The  intestinal  lesions 
— that  is,  the  tumefied  lymphoid  tissue,  necrosis,  and 
ulceration  that  occur  so  commonly  in  the  intestinal  form 
of  cholera — may  occur  in  the  intestine  of  swine  that  are 
not  infected  with  the  filterable  virus.     Necrosis  and  ul- 


INFECTIOUS  DISEASES 


185 


ceration  have  been  observed  as  a  result  of  infection  with 
the  Bacilhis  necrophorous,  and  these  lesions  have  also 
been  observed  in  swine  that  had  been  fed  excessive  quan- 
tities of  ferrous  and  copper  sulphate. 

The  study  of  the  lesions  gives  assistance  in  the  diag- 
nosis of  cholera.  The  pneumonic  lesions  are  relatively 
common  in  cases  of  cholera  excepting  in  the  peracute 


I 


Fig.  15.— ACUTE  HOG  CHOLEKA,    (Advanced  Stage). 


type.  The  lesions  in  the  lung  consist  of  croupous  pneu- 
monia in  some  stages  and  involve  the  cardiac  and  fre- 
quently the  cephalic  lobe.  This  lesion  cannot  be  consid- 
ered characteristic  of  cholera  as  it  is  the  typical  lesion  of 
croupous  pneumonia,  but  when  it  occurs  in  conjunction 
with  subserous  and  submucous  hemorrhages,  congestion 
and  hemorrhages  of  lymph  nodes,  and  discoloration  of 


186  SWINE  DISEASES 

bone  marrow  the  evidence  is  in  favor  of  tlie  existence  of 
cholera. 

Swine  plague  is  distinguished  from  the  pectoral  form 
of  cholera  by  the  fact  that  the  former  is  characterized  by 
catarrhal  pneumonia  in  the  early  stages  of  the  disease, 
and  by  necrotic  pneumonia  in  the  later  stages,  and  also 
by  the  presence  of  fibrinous  pleurisy  with  or  without 
adhesions. 

Petechial  hemorrhages  of  the  kidney  were  formerly 
considered  pathognomonic  of  cholera,  but  these  hemor- 
rhages have  been  found  in  the  kidney  rather  frequently 
when  cholera  was  absent,  or  at  least  the  blood  from  such 
cases  failed  to  produce  cholera  in  healthy,  susceptible 
pigs. 

Engorgement  of  the  spleen  is  a  common  lesion  in 
acute  cholera,  but  this  condition  sometimes  occurs  as  a 
result  of  disturbed  digestion  and  as  a  result  of  leukemia, 
and  is  a  common  lesion  of  other  septicemic  diseases. 
Therefore  enlarged  spleen  alone  should  not  be  considered 
a  sufficient  evidence  upon  which  to  base  a  diagnosis  of 
cholera. 

The  congestion  and  hemorrhage  of  the  lymph  nodes 
is  one  of  the  most  common  and  characteristic  lesions  of 
cholera,  but  this  lesion  is  not  always  present.  Hemor- 
rhages of  the  subserosa  and  submucosa  are  quite  constant 
in  cholera;  however,  they  may  occur  in  any  other  septi- 
cemia. The  changes  of  the  bone  marrow,  although  oc- 
curring to  a  less  degree  in  other  septic  conditions,  are 
among  the  most  characteristic  lesions  of  cholera,  but  this 
lesion  is  absent  in  some  of  the  peracute  cases.  Petechial 
hemorrhages  are  also  of  common  occurrence  in  swine 
erysipelas,  but  this  disease  can  be  differentiated  from 
cholera  by  the  demonstration  of  the  organism  of  swine 
erysipelas  in  the  blood  or  splenic  pulp. 

The  principal  diagnostic  lesions  of  cholera  are  sub- 
serous and  submucous  hemorrhages,  congestion  and 
hemorrhages  of  the  lymph  nodes,  and  the  discoloration  of 
the  bone  marrow.  Next,  in  order  of  frequency,  is  croup- 
ous pneumonia  of  the  cardiac  lobe  of  the  lung. 


INFECTIOUS  DISEASES 


187 


111  the  diagnosis  the  history  of  the  outbreak,  and  par- 
ticularly the  distance  from  known  cases  of  cholera  and 
whether  or  not  any  swine  have  recently  been  introduced, 
must   always   be   taken    into   consideration.     Finally,    it 


^ 


life-     16.— llKAiiT     SHOWING     TISSUE     HKMOKRHAGES     1>UE    TO 

HOG    CH01.EKA. 

IJ.   Hyperemlc  areas. 


188 


SWINE  DISEASES 


must  be  understood  that  the  only  absolute  method  for 
the  diagnosis  of  cholera  at  this  time  is  the  inoculation  of 
a  known,  healthy,  susceptible  pig  vdih  from  one  to  five 
cubic  centimeters  of  blood  from  the  suspected  animal. 
Thus  determine  the  presence  or  absence  of  cholera. 


Fig.    17.— KIDNEYS. 

A.    Normal.     B.    hog-    cholera    (turkey    egg)    kidney. 


Prognosis. — The  peracute  septicemic  form  of  cholera 
is  nearly  always  fatal.  An  occasional  animal  may  recover 
from  the  ordinarily  acute  septicemic  type,  but  the  large 
percentage  so  affected  succumb.  The  pectoral  form  is 
usually  quite  fatal,  in  some  localities  fully  ninety  percent 
of  the  affected  swine  dying.     The  intestinal  form  is  less 


INFECTIOUS  DISEASES 


189 


fatal  and  has  a  tendency  to  become  chronic,  the  course  in 
such  cases  varying  from  one  week  to  two  or  three  months. 
Treatment. — It  is  probable  that  more  proprietary 
remedies  have  been  devised  and  advertised  as  hog-cholera 
cures  than  for  any  other  disease  of  domesticated  animals. 
The  application  of  therapeutic  agents  other  than  anti- 
hog-cholera  serum  has  not  proved  satisfactory  in  any 
proved  outbreak  of  cholera. 


Fig.    1«.— LYMPH    XODE?;. 
A.   Normal.     B.  hypereniic   due  to  hog   cliolera. 


With  this  disease,  as  with  any  other,  prevention  is 
far  better  than  treatment  of  afflicted  animals.  It  is  a 
preventable  disease,  but  unfortunately  it  has  been  re- 
sponsible for  extensive  losses  of  swine  for  so  many  years, 
in  practically  every  country,  that  the  swine  breeders 
and  swine  raisers  have  apparently  become  accustomed  to 
the  losses  and  accept  them  as  a  matter  of  fact,  and  until 
recently  with  little  concern  as  to  methods  of  pre^•ention. 
The  prevention  of  hog  cholera  may  be  accomplished  by 


190  SWINE  DISEASES 

complying  with  the  laws  of  hygiene,  the  enforcement  of 
sanitary  police  regulations,  and  by  immunization  of  swine 
by  the  use  of  anti-hog-cholera  serum. 

The  laws  of  hygiene  of  other  domesticated  animals 
than  swine  are  fairly  well  provided  for  by  the  stock 
raisers.  It  has  been  the  custom,  and  it  is  still  far  too  com- 
mon at  the  present  writing,  to  consider  that  anything  is 
good  enough  for  swine.  Thus  many  men  having  exten- 
sive financial  interests  in  pork  production  are  constantly 
seeking  fermented  grain  and  moldy  and  otherwise  spoiled 
or  damaged  foods  for  their  swine  because  such  food  stuff 
can  usually  be  purchased  for  less  money  than  a  clean, 
wholesome  food.  But  such  foods  interfere  with  the  diges- 
tion, thus  weakening  the  animals  and  rendering  them 
more  susceptible  to  disease.  Swine  that  are  given  the 
proper  diet  arc  not  necessarily  immune  to  cholera,  but 
they  are  much  more  resistant  than  swine  affected  with 
digestive  derangements.  Swine  should  also  receive  an 
abundance  of  clean,  wholesome  water,  and  not  be  required 
to  drink  water  from  polluted  streams  or  stagnant  pools. 
Many  cases  of  what  would  probably  have  been  fatal  cases 
of  cholera  have  been  nursed  back  to  health  by  providing 
good  surroundings  and  a  diet  of  clean,  sweet  milk. 

Hog  pens  should  not  be  placed,  as  they  frequently  are, 
in  locations  that  cannot  be  drained  properly.  It 
is  not  necessary  for  swine  to  have  mud  and  filth  for  their 
existence.  They  will  thrive  better  when  kept  in  sanitary 
quarters. 

Sanitary  police  regvdations,  or  general  sanitation  in 
relation  to  control  of  hog  cholera,  have  certainly  not 
received  proper  consideration.  If  rides  and  regulations 
were  instituted  prohibiting  the  dissemination  of  hog 
cholera,  the  losses  could  be  rapidity  diminished.  The 
following  provisions  for  quarantine  and  shipping  regula- 
tions were  recommended  by  the  committee  on  Uniform 
Methods  for  the  Control  of  Hog  Cholera  at  the  meeting 
of  the  United  States  Live  Stock  Association  in  December, 
1913: 

1.  The  shipment  or  movement,  interstate,  of  swine  affected  with 
cholera  to  be  prohibited. 


INFECTIOUS  DISEASES  191 

2.  Exposed  swine  to  be  shipped  under  permit  and  placard. 

3.  The  movement  of  cholera-infected  swine  over  the  public  high- 
ways to  be  prohibited. 

4.  Provision  for  moving  exposed  swine  under  permit  in  approved 
manner. 

5.  Carcasses  of  animals,  and  particularly  of  swine  that  have  died 
of  cholera,  to  be  burned  within  twenty-four  hours  after  death,  or  luider 
special  permit  to  be  disposed  of  other\\"ise. 

6.  The  shipment  by  rail  of  swine  for  purposes  other  than  immediate 
slaughter  to  be  permitted  only  through  special  pens  and  unloading 
chutes,  or  through  portable  chutes  directly  into  wagons.  If  imloaded 
in  regular  loading  pens,  to  be  moved  imder  permit  in  approved  manner. 

7.  Public  stock  yards  to  be  under  close  super\Tsion  and  cleaned 
and  disinfected  at  intervals  determined  by  the  proper  state  authorities. 

8.  Railway  cars  for  the  transportation  of  swine  other  than  such  as 
are  intended  for  immediate  slaughter  to  be  cleaned,  washed,  and  dis- 
infected before  swine  are  loaded. 

9.  All  cars  in  which  diseased  swine  are  found,  or  in  which  exposed 
swine  were  shipped  for  immediate  slaughter,  to  be  cleaned,  washed, 
and  disinfected  within  twenty-four  hours  after  unloading,  or  cars  to 
be  held  until  the  presence  or  absence  of  diseases  has  been  determined. 

10.  All  cars  or  vehicles  of  transportation  carrying  cholera-exposed 
swine  to  be  placarded  in  a  conspicuous  manner,  "Cholera  Exposed 
Swine  for  Immediate  Slaughter." 

11.  Owners  of  swine  and  persons  in  charge,  including  attending 
veterinarians,  to  report  without  delay  to  state  authorities  all  outbreaks 
of  cholera  among  swine. 

12.  Live-stock  sanitary  authorities  to  quarantine  all  infected  herds 
and  premises,  but  may  permit  shipment  of  exposed  swine  for  immediate 
slaughter  as  above  provided. 

13.  Infected  premises  to  be  quarantined  not  less  than  sixty  days 
after  last  traces  of  disease  have  disappeared  and  premises  have  been 
cleaned  and  disinfected. 

14.  Infected  premises  to  be  cleaned  and  disinfected  under  super- 
vision prescribed  by  live-stock  sanitary  authorities. 

15.  The  live-stock  sanitary  authorities  to  be  given  power  to  provide 
in  a  practicable  manner  against  the  dangerous  pollution  of  streams 
with  hog-cholera  virus  and  pro^•ide  for  the  safe  disposal  of  garbage 
liable  to  be  infected  with  hog-cholera  virus. 

16.  To  prevent  the  spread  of  hog  cholera  bj-  swine  shown  for  exhi- 
bition purposes,  such  swine  to  be  treated  with  serum  and  virus  not  less 
than  forty  daj's  prior  to  the  opening  date  of  the  exhibit,  or  with  serum 
alone  not  more  than  fifteen  days  before  such  time. 

17.  Provision  for  controlling  for  thirty  days,  by  quarantine  or 
otherwise  when  deemed  advisable  by  the  proper  authority,  of  all  swine 
treated  with  serum-virus,  or  premises  on  which  such  swine  are  kept, 
to  prevent  danger  of  possible  spread  of  infection  from  inoculated  animals. 

If  the  above  or  similar  regulations  could  be  instituted 
and  enforced  there  is  no  doubt  that  cholera  in  swine 
would  be  materially  diminished  and  could  be  eradicated, 
ultimately,  by  the  judicious  use  of  serum,  from  this  or 
any    other    country.     Since    ths    advent    of    anti-hog- 


192  SWINE  DISEASES 

cholera  serum  the  euforcement  of  sanitary  regulations 
has  been  neglected.  In  order  to  obtain  and  enforce 
ejfficient  sanitary  measures  the  pork  producers  must  first 
be  educated  to  the  necessity  of  such  measures. 

The  application  of  some  of  the  simple  sanitary  rules 
have  proved  of  great  monetary  value  to  swine  raisers. 
As  an  illustration,  the  separation  of  the  infected  from  the 
healthy  swine  by  means  of  a  clinical  thermometer,  and 
the  proper  after-care,  have  been  the  means  of  saving  over 
fifty  percent  of  many  infected  herds. 

If  more  consideration  were  given  to  proper  hygienic 
care  and  sanitary  control,  and  less  to  the  production,  dis- 
tribution, and  application  of  serum,  it  is  possible  that 
hog  cholera  would  soon  become  a  much  less  serious  dis- 
ease economically. 

Preventive  Treatment. — The  first  use  of  serum  for 
the  prevention  of  hog  cholera  was  made  in  1897  by 
Preisz,  who  obtained  it  from  a  swine  that  had  recovered 
from  cholera.  In  1904  De  Schweinitz  and  Dorset  de- 
monstrated that  hog  cholera  was  caused  by  a  filterable 
virus,  and  soon  thereafter  Dorset,  McBryde,  and  Niles 
devised  a  plan  of  hyperimmunizing  swine  for  the  purpose 
of  producing  anti-hog-cholera  serum.  This  serum  came 
into  general  use  about  1908,  and  is  now  being  used  ex- 
tensively in  the  United  States.  It  is  prepared  on  the 
following  general  plan,  different  manufacturers  having 
slightly  different  methods. 

The  production  of  serum  is  of  considerable  importance 
and  a  brief  description  of  the  general  process  follows : 

Swine  having  a  large  carcass  and  weighing  225  to  275 
pounds  are  selected,  and  if  they  are  not  known  to  be  im- 
mune they  are  immunized  by  using  twenty-five  to  thirty- 
five  cubic  centimeters  of  serum  to  the  hundred  pound  hog 
weight,  and  from  one  to  two  cubic  centimeter  of  virus. 
The  swine  used  for  hyperimmunes  are  tuberculin  tested 
and  reactors  are  discarded.  After  the  swine  has  recovered 
from  the  immunizing  process,  which  requires  from  ten 
to  twenty  days,  it  is  then  hyperimmunized.  A  pre- 
requisite   of    the    hyperimmunizing    process    consists    in 


INFECTIOUS  DISEASES  193 

having  all  instruments,  bottles,  and  so  on,  sterile,  and  of 
having  environments  that  are  conducive  to  asepsis.  The 
immune  swine  that  are  to  be  hyperimmunized  should  be 
kept  in  a  pasture  or  yards  that  are  concreted  to  prevent 
undue  filthiness.  The  virus  used  may  be  obtained  from 
the  field,  that  is,  from  natural  outbreaks  of  cholera,  or  it 
may  be  produced  by  injecting  healthy,  susceptible  pigs 
^•itli  one  to  two  cubic  centimeters  of  virus.  A  pig 
weighing  from  sixty  ro  ninety  pounds  is  usually  used. 
The  virus  pigs  should  be  carefully  observed,  and  tempera- 
ture records  maintained.  If  susceptible  pigs  have  been 
injected  ^"ith  a  virulent  ^^rus  there  will  be  evidence  of 
the  disease  in  four  to  seven  days,  and  from  the  seventh 
to  the  ninth  day  the  temperature  of  the  pig  will  probably 
range  from  105  to  108  degrees  Fahrenheit,  and  is  then 
prepared  for  slaughter  by  thoroughly  washing  and  apply- 
ing some  disinfectant  to  the  skin  of  the  venter  surface  of 
the  body.  In  addition  to  these  precautions  the  inferior 
cer^^cal  region  is  shaved.  The  entire  pig  is  shrouded  with 
moist,  antiseptic  gauze  to  prevent  any  particles  of  dust 
from  dropping  into  the  vessels  used  in  collecting  the  virus. 
The  vessels  are  severed,  and  the  blood  is  collected  in  a 
sterile  vessel  and  the  fibrin  whipped  and  removed;  the 
remainder  of  the  blood  is  filtered  through  gauze,  and  con- 
stitutes the  virus  blood.  The  virus  pig  is  then  autopsied, 
and  if  lesions  of  cholera  are  not  found,  or  if  lesions  of 
other  diseases  are  found,  the  collected  virus  blood  is 
discarded.  The  collection  of  field  virus  requires  the  same 
precaution. 

Hyperimmunizing  may  be  accomplished  by  the  intra- 
peritoneal, intravenous,  or  intramuscular  injections  of  virus. 
The  quantity  of  virus  employed  depends  upon  the  method 
used,  that  is,  the  slow  or  quick  method.  For  the  intravenous 
and  intramuscular  methods  five  cubic  centimeters  of  virus 
are  used  to  the  pound  weight  of  the  hog  that  is  being  hyper- 
immunized. This  quantity  is  divided  and  given  in  two 
injections  in  the  slow  process  and  as  a  single  injection  in 
the  quick  process.  In  the  intravenous  method  the 
injection  is  made  in  an  ear  vein  after  properly  cleaning  and 


194 


SWINE  DISEASES 


V 


J 


t  , 


Fili.    19.— VIRUS    JJI.EKDING    ROOM. 
1.   Revolving:   door  upon   which  the  pis:  is   secured  and   cleaned.     The 
door   is   then   turned,    which   brings   the    pig    into    the   bleeding   room. 
■i.  shrouded    pig. 


INFECTIOUS  DISEASES  195 

securing  the  animal.  Various  devices  are  used  in  making 
the  injection.  The  principle  involved  is  to  force  the  virus 
into  the  vein  il,:>v\ly.  Ihe  virus  iihcikl  be  near  the  body 
temperature  when  injected.  In  the  intra-muscular  meth- 
od the  virus  is  injected  in  the  interstices  between  the 
muscle  bundles,  selecting  two,  three,  or  four  locations, 
as  the  inner  thigh  muscles  and  the  subscapular  region. 
The  intraperitoneal  injection  is  made  by  passing  a  long 
needle  through  the  abdominal  parietes  into  the  peri- 
toneal cavity. 

The  hyperimmunes  are  kept  in  clean,  sanitary  pens 
and  a  temperature  record  maintained  in  order  that  the 
producer  may  know  when  the  reaction  is  over.  ^Yhen 
the  temperature  assumes  the  normal  the  blood  contains 
the  antibodies.  Two  methods  of  bleeding  hyperimmunes 
are  in  use — the  slaughter  method  and  tail  bleeding.  By 
the  slaughter  method  practically  all  of  the  blood  is  ob- 
tained. By  the  tail-bleeding  process  from  two  to  four 
bleedings  are  made,  and  the  swine  are  re-hyperimmunized, 
and  after  the  reaction  they  are  used  for  bleeding.  Some- 
times the  hyperimmune  is  tail  bled  for  one,  two,  or  three 
times  and  then  slaughtered.  Each  method  has  some 
advantages  and  some  disadvantages.  The  slaughter 
method  is  the  most  rapid — in  other  words,  more  serum 
can  be  produced  in  a  given  length  of  time  than  by  tail 
bleeding.  Tail  bleeding  is  the  most  economical  method 
of  producing  serum,  and  antiseptic  precautions  can  be 
carried  out  more  effectually. 

Proper  equipment  is  required  for  either  process,  and 
the  instruments,  bottles,  and  other  utensils  u^ed  must  be 
sterile  and  the  environment  must  be  conducive  to  asepsis. 

The  blood  obtained  from  hyperimmune  swine  is 
whipped,  the  fibrin  being  removed  and  the  remaining 
portion  of  the  blood  filtered  through  gauze.  When  ob- 
tained by  the  slaughter  method,  the  blood  from  each  hog 
is  kept  separately  until  the  carcass  is  autopsied  and  the 
absence  of  cholera  and  other  diseases  is  demonstrated. 
The  blood  may  also  be  kept  in  one  container.  Centrifu- 
gation  of  the  blood  is  being  practiced  by  some  producers. 


196 


SWINE  DISEASES 


Fig.    20.— HYPERIMMUNIZIXG   ROOM. 
1.  Virus    container    showing-    attaclinient   to   pressure   tank.     2.  needle 
inserted  into  the  ear  vein. 


INFECTIOUS  DISEASES  197 

and  this  should  be  encouraged,  as  a  cleaner  product  and 
one  that  is  more  easily  injected  is  produced.  The  blood 
obtained  from  hyperimmune  swine  by  either  process  is 
preserved  by  adding  a  small  percentage  of  phenol  or 
trikresol  and  properly  sealed  and  placed  in  storage  at  a 
temperature  of  about  50  degrees  Fahrenheit.  Before  the 
serum  is  used  it  is  tested.  First,  second,  third,  and  fourth 
bleedings  from  different  hyperimmunes,  or  the  blood  from 
different  hyperimmunes  obtained  by  slaughtering,  are 
mixed  up  to  quantities  of  80,000  cubic  centimeters.  This 
amount  constitutes  a  series,  and  therefore  each  series  is 
a  composite  serum.  For  a  test  sample  a  proportionate 
quantity  is  taken  from  each  separate  quantity  that  makes 
up  a  series.  The  sample  should  be  obtained  immediately 
after  bleeding,  thus  obviating  reopening  of  the  bottles. 

For  the  test  eight  healthy,  susceptible  pigs,  weighing 
from  sixty  to  ninety  pounds  each,  are  selected.  These 
pigs  are  maintained  in  four  separate  pens  of  two  each. 
The  test  is  made  as  follows:  Each  of  the  eight  pigs  is 
injected  with  two  cubic  centimeters  of  virus;  pigs  No.  1 
and  No.  2  receive  twenty -five  cubic  centimeters  of  serum; 
pigs  Nos.  3  and  4  receive  twenty  cubic  centimeters  of 
serum;  pigs  No.  5  and  6  receive  fifteen  cubic  centimeters 
of  serum;  and  pigs  Nos.  7  and  8  receive  the  virus  only. 
Figs  Nos.  7  and  8  are  designated  check  pigs,  and  they 
should  show  visible  symptoms  and  die  of  typical  cholera 
within  twelve  to  eighteen  days.  A  temperature  record 
is  maintained  for  twenty  days,  and  from  observing  this 
record  the  virulency  of  the  virus  and  the  potency  of  the 
serum  can  in  a  measure  be  determined.  The  following 
chart  is  the  record  of  a  serum  test:   (See  p.  198.) 

This  test  is  not  absolute,  but  it  is  of  value  as  an  indi- 
cator. The  test  should  be  repeated  if  the  following  con- 
ditions arise.  First,  if  the  check  pigs  should  not  show 
any  evidence  of  cholera  within  ten  to  fifteen  days;  sec- 
ond, if  the  check  pigs  or  any  of  the  other  six  should  show 
a  constant  high  temperature  beginning  on  the  second, 
third,  or  fourth  day  after  the  test  begins;   third,  if  either 


198 


SWINE  DISEASES 


RECORD   OF   SERUM   TEST 


Date  Begun. 
Date  Ended. 


Virus  Used,  Lot  No.. 


.19 

-19__  Quantity  Tested. 
Series 


DESCRIPTION 

TEMPERATURES 

Tag 

No. 

89 
90 
91 
92 

Sex 

F 
M 
M 

F 

^,       5/30     5/31 
Wt.    Temp. 

6/1 

2.2 
1.6 
2.4 

2.8 

6t2 

2.4 
1.8 
2.2 
2.7 

6t3 

3.0 
1.8 
2.8 
2.0 

6/4 

3.0 
2.0 
3.1 
2.4 

6/5 

2.4 
1.8 
4.2 
2.4 

6/6  6/8 

2.0  1.4 
i 

2.2  2.0 

3.2  2.8 

2.1  2.2 

6/9 

1.4 
2.2 
3.0 
2.1 
2.6 
2.4 

4.8 
6.2 

6/10 

1 

__ 
2.6 

2.0 

25  Cc.  Serum 
2  Cc.  Virus 

84 
88 
77 
87 

2.4 
1.4 

1.4 

2.0 

20  Cc.  Serum 
2  Cc.  Virus 

2.6 
3.8 

2.0 
3.2 

3.2 

2.2 

15  Cc.  Serum 
2  Cc.  Virus 

93 
94 

95 
96 

F 

M 

F 
M 

70 

SI 

2.4       3.0 

2.8       3.2 

2.2 
2.8 

2.0 
2.4 

2.6 
2.6 

2.4 
2.5 

2.3 
2.6 

4.8 
4.2 

2.4 
3.0 

5.2 
4.0 

1.8 
2.6 

4.0 
6.4 

1.6 
2.6 

2  Cc.  Virus 
2  Cc.  Virus 

45         3.6 
47         3.2 

3.4 
4.0 

3.6 
3.2 

3.4 
3.4 

4.6 
3.6 

5.4 
3.7 

5.2 
6.0 

RECORD  OF  SERUM  TESTS— Continued 


DAYS 

POST   MORTEM   LESIONS 

6/II 

6/12  6/13 

1.4     1.2 
2.0     1.8 
3.0,   2.8 
2.2'  2.4 
2.0    2.3 
2.6    2.8 

5.6    5.8 
6.0    5.4 

6/14  6/15 

1.0  98.6 
1.31   1.2 
2.5|  2.2 
2.0'  2.2 
2.1|  2.4 
2.5    2.6 

5.1;  5.2 
5.0    5.0 

6/16  6/17 
Skin 

1 
1.0     1.2 
1.4     1.6 
2.0     2.0 
2.2     2.4 
2.6     2.6 
2.8     2.6 

1  died 

5.4     5.8 

died 

5  2     5.6 

6/18 

m  S 

J3^ 

0. 
m 

c  u 

s  " 

El 

-0 

ta 

1.6 
2.2 

98.4 
1.4 
2.6 
2.2 
1.3 
2.2 

M 
M 

3.4 
2.0 

2.2 
2.8 

M 
M 

s 

M 

5.4 
6.2 

M 

S 

M 
S 

M 
M 

M 

M 

M 
M 

S 
M 

Key  to  Lesions:     S — Slight.     M — Well  Marked.     E — Extensive. 


PLATE  IL 


Fig.  1 


</ 


Fig.  2 


Fig.  1.  Thrombosis  of  the  hver,  showing  red  and 
white  thrombi  and  thrombi  in  which  decolorization  is 
just  taking  place. 

Fig.  2.  Lung  showing  hemorrhagic  areas  due  to  hog 
cholera. 


INFECTIOUS  DISEASES  199 

of  the  first  four  pigs  should  die  of  cholera  during  the 
time  of  the  test. 

The  serum  that  has  been  tested  and  in  which  the  two 
check  pigs  have  died  of  cholera  and  the  first  six  pigs  have 
shown  no  visible  illness  nor  any  constant  rise  of  tem- 
perature is  ready  for  mixing  and  bottling,  after  which  it 
is  ready  for  use.  The  laboratory  for  mixing  and  bottling 
must  be  properly  constructed  in  order  that  contamination 
of  the  serum  may  be  reduced  to  a  minimum  and  the  neces- 
sary equipment,  such  as  sterilizers,  must  be  provided. 

For  mixing  the  serum  a  container  must  be  selected 
that  can  be  sterilized  and  from  which  the  serum  can  be 
bottled. 

After  thoroughly  mixing  the  serum  constituting  a 
series  it  is  withdrawn  into  sterile  bottles,  the  size  of  which 
will  be  determined  by  the  demand.  The  bottles  are 
properly  sealed,  labeled,  and  wrapped,  and  until  needed 
put  back  in  storage  at  a  temperature  not  to  exceed  50 
degrees  Fahrenheit. 

The  foregoing  description  is  the  general  method  of 
production  of  anti-hog-cholera  serum.  Many  little  fac- 
tors that  are  of  considerable  importance  have  not  been 
enumerated.  The  accompanying  illustrations  may  con- 
vey some  idea  of  the  problems  of  the  production  of  this 
product.  The  production  of  anti-hog-cholera  serum  has 
become  of  such  vast  importance  to  the  swine  industry 
of  the  country  that  Congress  has  provided  means  for  its 
regulations  in  order  that  a  potent  serum  may  be  obtained. 

The  following  report  of  the  committee  on  Uniform 
Methods  for  the  Control  of  Hog  Cholera  was  adopted 
by  the  United  States  Live  Stock  Sanitary  Association 
in  Chicago,  December,  1913,  and  is  a  brief  statement  of 
the  requirements  for  serum  production : 

Serum  Production 

Location  of  buildings. 

Location  to  be  such  that  surroundings  will  not  interfere  with  sanitary 
production  and  that  their  operation  will  not  contaminate  surrounding 


200 


SWINE  DISEASES 


Construction  of  buildings. 

The  oonstruction  of  buildings  to  be  of  material  that  will  permit  of 
daily  cleaning  and  disinfection,  stone,  brick,  tile,  and  concrete  being 
especially  recommended. 

Arrangement  of  plant. 

1.  The  arrangement  and  equipment  of  buildings  to  be  such  as  to 
insure  the  production  of  a  pure  and  uncontaminated  product. 

2.  Swine  to  be  kept  in  separate  buildings  located  a  suflBcient  distance 
from  the  building  containing  the  bleeding  (either  virus  or  serum)  and 
hyperimmunizing  rooms  and  in  which  swine  are  to  be  placed  for  the 
latter  purpose  only. 


Fig.    31.— SERUM    CENTRIFUGIXG    ROOM. 
1.  A  ten-quart  centrifuge.     3.  a  four-quart  centrifuge. 

3.  The  serum  bleeding  room,  the  virus  bleeding  room,  and  the 
hyperimmunizing  room  to  be  separate  and  distinct  rooms. 

4.  The  preparation  of  serum,  and  the  preparation  of  virus  from  the 
whole  blood,  to  be  operations  conducted  in  separate  and  distinct  rooms 
without  direct  communication  with  each  other  or  with  the  foregoing 
not  larger  than  an  opening  which  will  permit  the  transfer  of  receptacles 
containing  the  freshly  drawn  blood,  and  to  be  used  for  no  other  purpose. 

5.  Separate  washing  and  sterilizing  rooms  to  be  provided. 

C.  The  prepared  serum  and  virus  to  be  stored  in  properly  cooled 
rooms. 

I  7.  Swine  kept  for  virus  production  and  the  testing  of  serum  to  be 
properly  isolated  so  as  to  reduce  to  a  minimum  the  danger  of  spreading 
infection.  Separate  and  di.stlnct  feed  rooms  to  be  provider!  for  such 
animals. 


INFECTIOUS  DISEASES 


201 


8.  Mortuary,  crematory,  abattoir,  and  desiccating  or  rendering 
plant  operated  for  utilizing  tlie  waste  products  of  the  establishment 
to  be  located  so  as  to  prevent  contamination  from  this  source. 

9  Nocessary  dressing  and  toilet  rooms,  properly  equipped  and 
located,  to  be  provided.     Also  bottling  and  packing  rooms. 

10.  Provision  for  the  sanitary  disposal  of  all  manure,  offal  and 
debris. 

Operation. 

1.  The  operation  of  serum  plants  to  be  imder  the  direct  super- 
vision of  a  competent  veterinarian  or  other  professional  man  whose 
training  and  experience  have  fitted  him  for  this  work. 

2.  Prohibition  of  the  sale  of  serum  and  virus  produced  from  animals 
affected  with  any  contagious  disease  other  than  hog  cholera  and  of 
any  contaminated  serum  or  virus. 


Fig.   23.— STERinZIXG    ROOM. 
1.  Electric  sterilizer.     3.  autoclave.     3.  type  of  utensil  used  for  collect- 
ing: blood. 

3.  Provision  requiring  full  and  complete  records  of  all  steps  in  the 
manufacture  and  test  of  serum  or  virus. 

4  The  label  on  the  container  of  serum  or  \nru.s  to  show  the  true 
name  of  the  product,  the  name  or  number  of  the  manufacturer,  the  date 
of  preparation,  or  the  date  after  which  the  manufacture  no  longer 
guarantees  the  product,  anil  a  serial  number  to  identify  the  product 
with  the  records  of  the  establishment. 

Two  general  methods  are  utilized  in  the  immunization 
of  swine  with  anti-hog-cholera  serum — the  serum  alone 
method  and  the  simultaneous  method. 


202  SWINE  DISEASES 

The  exact  method  of  administering  serum  has  been 
freely  discussed  at  various  associations,  and  numerous 
articles  have  appeared  in  various  publications.  The 
operator  must  always  provide  clean  and  sterile  instru- 
ments. It  is  true  that  the  instruments  become  con- 
taminated as  soon  as  used,  but  at  least  two  needles  should 
be  provided  in  order  that  one  may  be  placed  in  a  disin- 
fecting solution  w^iile  the  other  is  in  use.  The  syringe 
should  be  sterilized  by  boiling  after  being  used  for  a  few 
hours  or  after  a  herd  has  been  immunized,  before  using 
it  on  another  herd.  The  serum  and  virus  should  be  in- 
jected deeply  into  the  muscle  in  order  to  insure  rapid 
absorption.  Bad  results  frequently  are  the  result  of 
failure  of  absorption  of  the  serum  or  virus  that  has  been 
injected  just  beneath  the  skin  in  the  subcutaneous  fat. 
Swine  that  are  in  filthy,  muddy  pens  should  not  be  in- 
jected because  of  the  probability  of  infection  in  the  needle 
wounds,  and  swine  that  have  quantities  of  mud  or  filth 
upon  their  bodies  should  not  be  injected.  All  swine  that 
are  injected  should  be  reasonably  clean,  the  point  of 
injection  should  be  painted  with  tincture  of  iodine,  and 
the  skin  should  be  pinched  after  withdrawing  the  needle 
to  prevent  leakage. 

The  serum-alone  method  produces  an  immunity  for  a 
period  of  from  one  week  to  three  months,  but  it  does  not 
entail  any  danger  of  infecting  and  producing  cholera  in 
a  cholera-free  herd  and  establishing  new  centers  of  cholera 
in  a  community  free  of  the  disease.  By  the  proper  use 
of  serum  alone  in  communities  where  there  are  only  a 
few  centers,  cholera  could  be  efficiently  controlled.  In 
such  cases  the  infected  herd  and  all  surrounding  herds 
should  be  immunized  and  if  necessary  the  process  could 
be  repeated  six  weeks  later.  This  method  of  control  is 
not  as  applicable  when  several  counties  of  a  state,  or  the 
entire  state,  is  infected.  Serum  alone,  when  given  in 
large  doses,  is  of  considerable  value  in  the  incubation 
period  of  the  disease  before  the  animals  show  visible 
symptoms  but  after  the  temperature  has  risen.  The 
judicious  use  of  serum  in  such  cases  has  saved  as  high  as 


INFECTIOUS  DISEASES 


203 


eighty  or  ninety  percent  of  the  exposed  herd.  The  serum 
alone  is  recommended  for  immunizing  pregnant  sows, 
because  the  simultaneous  method  frequently  produces 
abortion.  This  method  should  also  be  used  to  immunize 
swine  that  are  to  be  introduced  into  healthy,  susceptible 
herds. 

The  dose  of  the  serum  in  the  serum-alone  treatment 
should  not  be  less  than  thirty  cubic  centimeters  for  each 
hundred-pound  live  weight  of  hog. 

The  simultaneous   method  is  used   more  extensively 


Fig.   23.— CHOLEKA-IMMrXE   HOGS. 

There  is  a  Arm  at  the  Stock  Yards  in  Chicago  manufacturing  anti-liog 
cholera  serum  that  makes  a  business  of  va<  einating  hogs,  that  are 
to  be  kept  in  the  Yards,  at  Sl.OO  per  hundred  pounds  and  guarantee- 
ing the  owners  against  loss.  These  hogs  are  kept  in  the  Yards  from 
three  \veeks  to  t«o  months  and  are  driven  about  frojn  pen  to  pen 
to  clean  up  the  feed  left  by  other  animals.  They  are  of  course 
continuiilly  exposed  to  virulent   infection. 

than  the  serum  alone,  because  it  produces  a  longer  im- 
munity. The  dose  of  serum  used  in  the  simultaneous 
method  should  be  fifty  percent  more  than  the  dose  in  the 
serum-alone  method.  The  serum  and  virus  must  be  in- 
troduced separately  in  different  parts  of  the  body. 

This  method  may  be  used  successfully  in  exposed 
herds,  especially  in  those  swine  that  do  not  show  a  high 
temperature.  But  the  virus  should  not  be  given  to  hogs 
that  are  showing  visible  signs  of  cholera. 

The  one  serious  disadvantage  of  the  simultaneous 
method  is  the  fact  that  infection  is  introduced.     Good 


204  SWINE  DISEASES 

authorities  claim  that  a  hog  immunized  by  the  simul- 
taneous method  does  not  eliminate  the  virus  unless  he 
dies  of  the  disease,  but  this  statement  has  not  been  clearly 
proved.  Even  though  the  virus  is  eliminated  only  in 
case  of  fatal  illness  of  the  immunized  hog,  the  procedure 
is  dangerous  to  say  the  least.  The  extensive  epizootic 
of  hog  cholera  in  Iowa  and  adjoining  states  in  1913  bears 
the  earmarks  of  the  results  of  infection  from  simultaneous 
immunization. 

To  say  the  least,  the  use  of  the  simultaneous  method  is 
contrary  to  good  sanitation. 

A  so-called  double  method  has  been  advocated  by 
some  for  the  prevention  of  cholera.  It  consists  of  the 
serum-alone  immunization,  followed  ten  days  later  by 
the  simultaneous  method.  This  method  is  quite  efficient, 
but  is  rather  expensive. 

In  time,  the  application  of  serum  in  the  control  of 
hog  cholera  will  be  rationally  adjusted,  and  this,  combined 
with  the  proper  enforcement  of  efficient  sanitary  regula- 
tions, will  result  in  diminishing  the  losses  from  this  dis- 
ease, and  the  swine  industry  may  then  be  profitably  pur- 
sued. 

SWINE  PLAGUE 

Swine  plague  is  a  specific  infectious  disease  caused 
by  the  Bacillus  suisepticus  and  is  characterized,  except 
in  the  septicemic  form,  by  a  catarrhal  and  necrotic 
pneumonia,  with  or  without  a  fibrinous  pleurisy. 

The  existence  of  this  disease  is  doubted  by  some  good 
authorities.  In  various  sections  of  the  United  States  a 
disease  of  swine,  primarily  confined  to  the  lung  and  pleura 
and  in  its  manifestations  distinct  from  cholera,  has  been 
observed.  The  same  disease  has  been  identified  in  various 
other  countries  by  other  investigators.  This  disease  is 
not  so  fatal,  neither  is  it  so  widespread,  as  cholera.  It 
may  occur  sporadically  or  enzoijtically,  but  it  rarely 
.assumes  an  epizootic  form.  The  percentage  of  losses  in 
affected  herds  varies  from  one  percent  to  seventy  percent. 

Etiology. — The  cause  of  swine  plague  is  the  Bacillus 
suisepticus.     This  microorganism  is  a  representative  of 


INFECTIOUS  DISEASES  205 

the  hemorrhagic  septicemia  group.  The  Bacillus  suisep- 
ticus  is  a  short,  bipolar-staining,  polymorphic,  nonmotile 
organism,  and  does  not  form  spores.  The  organism 
grows  readily  on  practically  all  culture  media,  aerobically 
or  anaerobically.  It  does  not  liquefy  gelatine  or  coagulate 
milk,  and  is  not  stained  by  Gram's  method. 

Its  vitality  is  prolonged  for  from  five  to  fifteen  days 
in  soil,  feces,  and  water  when  not  exposed  to  sunlight,  but 
is  destroyed  in  two  or  three  days  by  desiccation,  and  is 
easily  destroyed  by  weak  antiseptics.  The  organism  is 
killed  in  twenty  minutes  by  a  temperature  of  fifty-eight 
degrees  Centigrade. 

Fowls,  rabbits,  and  guinea  pigs  are  susceptible  to  the 
pathogenic  action  of  these  organisms.  The  virulence  of 
the  Bacillus  suisepticus  is  quite  variable  and  is  likely  to 
vary  with  suddenness.  Intrapulmonary  injections  into 
swine  usually  produce  multiple  catarrhal  pneumonia 
succeeded  by  necrotic  pneumonia. 

Source  of  infection. — The  Bacillus  suisepticus,  hke 
the  other  representatives  of  this  group,  are  %s-idespread. 
They  are  frequently  found  in  the  respiratory  passages  of 
normal  swine.  Their  virulence  is  variable,  and  it  seems 
plausible  that  some  predisposing  condition  must  exist  in 
the  s^*ine  that  become  affected,  or  the  organism  suddenly, 
for  some  reason  unexplained,  becomes  sufficiently  virulent 
to  produce  the  disease.  In  the  most  severe  outbreaks  it 
appears  that  the  \arulent  organisms  are  transmitted  from 
the  diseased  to  the  susceptible  swine,  or  at  least  the  dis- 
ease becomes  enzootic  in  a  very  short  time. 

Channel  of  entrance. — The  usual  channel  of  en- 
trance is  by  way  of  the  respiratory  organs,  although  it  fs 
possible  that  the  organism  may  be  successfully  introduced 
through  the  digestive  tract  or  skin. 

Lesions. — The  very  acute  disease  is  septicemic  in 
form  and  is  characterized  by  petechial  hemorrhages  in  the 
skin  and  in  the  serous  and  mucous  membranes.  There 
may  also  be  some  enlargement  of  the  lymph  nodes  and  of 
the  spleen.  The  usual  form  of  the  disease  is  characterized 
by  catarrhal  pneumonia,  different  areas  of  the  lung  show- 


206  SWINE  DISEASES 

ing  dififerent  stages  of  progress  of  the  disease,  such  as  con- 
gestion, red  hepatization,  gray  hepatization,  and  later 
necrosis  in  which  the  necrotic  material  may  be  liquid  or 
caseous.  As  a  result  of  the  variation  of  the  progress  of 
the  disease  in  different  areas  the  affected  lung  has  a 
marbled  or  mottled  appearance.  There  are  some  inter- 
lobular infiltrations;  the  bronchial  and  mediastinal 
glands  may  contain  hemorrhages  or  necrotic  centers; 
the  pleura  is  usually  affected  with  a  fibrinous  pleurisy 
with  or  without  adhesions.  In  the  more  chronic  cases 
the  necrotic  foci  in  the  lung  become  more  numerous  and 
there  may  be  a  purulent  or  septic  pleurisy  due  to  the  dis- 
charge into  the  pleural  cavity  of  the  necrotic  pulmonary 
centers.     There  will  be  a  diffuse  redness  of  the  skin. 

Swine  plague  is  frequently  associated  with  hog  cholera, 
and  then  the  various  lesions  characterizing  that  disease 
will  be  present  also,  all  of  the  lesions  being  variously 
modified. 

Symptoms. — The  period  of  incubation,  at  least  in 
artificially  infected  cases,  is  of  short  duration,  rarely 
exceeding  two  days.  The  septicemic  type  is  ushered  in 
suddenly  with  a  high  temperature,  though  it  rarely  ex- 
ceeds 105  degrees  Fahrenheit,  accompanied  by  inappe- 
tence,  weakness,  and  little  tendency  to  move.  The  blush 
of  the  skin  due  to  hyperemia  may  be  observed.  This 
form  is  rapidly  fatal,  the  course  rarely  exceeding  twelve 
hours. 

The  ordinary  form  of  swine  plague  is  evidenced  by 
the  usual  symptoms  of  pneumonia,  such  as  short,  dry, 
spasmodic  cough,  dyspnea,  temperature  up  to  105  de- 
grees Fahrenheit,  a  disposition  on  the  part  of  the  affected 
animals  frequently  to  sit  on  their  haunches  like  a  dog, 
mucous  or  mucopurulent  nasal  discharge,  diminished 
appetite  and  finally  cessation  of  appetite,  and  usually 
constipation.  As  the  disease  progresses,  breathing  be- 
comes more  difficult  and  there  is  extreme  w^eakness  and 
emaciation  if  the  affected  animals  live  long  enough. 
The  blush  of  the  skin  is  usually  present,  and  there  may  be 
conjunctivitis.     The  acute  form  usually  terminates  fatally 


INFECTIOUS  DISEASES  207 

in  about  one  week,  but  more  rarely  the  disease  becomes 
chronic. 

The  chronic  form  is  evidenced  by  spasmodic  cough, 
temperature  of  about  104  degrees  Fahrenlieit,  poor  appe- 
tite, emaciation,  and  weakness,  the  animals  usually  dying 
of  exhaustion  in  from  four  to  eight  weeks. 

Diagnosis. — The  diagnosis  of  swine  plague  is  attended 
with  considerable  difBculty.  The  septicemic  form  can 
be  distinguished  from  the  uncomplicated  septicemic  form 
of  hog  cholera  only  by  the  demonstration  in  the  blood  of 
the  Bacillus  suisepticus  or  the  presence  of  hog-cholera 
virus  by  the  production  of  hog  cholera  by  inoculation 
with  the  filtered  blood. 

From  the  pulmonary  form  of  hog  cholera  the  usual 
form  of  swine  plague  is  differentiated  only  by  autopsy. 
The  lung  lesions  in  hog  cholera  consist  of  a  typical  croup- 
ous pneumonia,  but  in  swine  plague  they  consist  of  a 
catarrhal  pneumonia  and,  in  the  later  stages,  of  necrosis 
Pleuritic  lesions  are  frequently  present  in  swine  plague. 

\  erminous  pneumonia  can  be  differentiated  from  swine 
plague  by  the  chronicity  of  the  attack,  the  wheezing  respi- 
ration, and  the  demonstration  on  autopsy  of  the  Stron- 
gylus  paradoxus. 

Catarrhal  pneumonia  is  differentiated  from  swine 
plague  by  the  fact  that  the  former  disease  occurs  only 
in  young  pigs  and  is  sporadic,  and  rarely  are  the  necrotic 
centers  typical  of  swine  plague  found  in  the  lung.  Pleuri- 
tic comphcations  are  also  the  exception  in  catarrhal 
pneumonia. 

Treatment.— Prevention  by  the  enforcement  of 
sanitary  regulations  is  much  more  effective  than  curative 
treatment.  The  disease  appears  to  be  favored  by  dry 
weather,  which  usually  insures  dusty  pens.  Wetting  of 
the  pens  with  water  or  some  dilute  disinfectant  prevents 
or  diminishes  the  spread  of  the  disease. 

The  use  of  a  bacterin  made  from  the  Bacillus  suisep- 
ticus, tried  out  in  a  few  herds,  has  not  given  uniformly 
good  results,  but  this  method  is-  worthy  of  further  trial 
and  it  is  possible  that   a  polyvalent  bacterin  prepared 


208  SWINE  DISEASES 

from  different  strains  of  the  different  species  of  the  repre- 
sentatives of  the  hemorrhagic  septicemic  group  would 
be  more  efficient. 

Immunization  by  means  of  a  serum  prepared  by 
repeated  injections  of  a  horse  with  cultures  of  the  Bacillus 
suisepticus  has  been  found  partially  successful,  but  the 
immunity  thus  produced  was  apparently  of  short  dura- 
tion. This  method  of  immunization  will  probably  not 
come  into  general  use. 

NECROBACILLOSIS 

Necrobacillosis  is  a  name  for  a  group  of  diseased 
conditions  caused  by  the  Bacillus  necrophorus  and  char- 
acterized by  inflammation  and  necrosis.  This  condition 
is  of  common  occurrence  in  one  form  or  other  in  various 
locations  in  the  United  States  and  in  other  countries. 
The  state  of  Colorado  has  suffered  extensive  losses  from 
necrobacillosis;  in  fact,  according  to  Glover,  the  losses 
from  this  disease  in  that  state  prior  to  1912  were  greater 
than  the  losses  from  cholera.  The  disease  occurs  sporadi- 
cally, enzootically,  and  rarely  as  an  epizootic. 

Etiology. — The  Bacillus  necrophorus  is  the  cause  of 
necrobacillosis.  This  microorganism  is  universally  dis- 
tributed, though  the  intestinal  tract  of  swine  may  be  its 
natural  habitat.  The  Bacillus  necrophorus  is  pleomor- 
phic, but  usually  occurs  in  long  threads  in  cultures  and 
in  the  invaded  tissues.  It  contains  granules,  particularly 
in  old  cultures.  It  is  nonmotile  and  does  not  form  spores. 
It  is  a  strict  anaerobe  and  grows  well  in  serum  agar, 
bouillon,  and  milk.  A  pungent,  disagreeable  odor  is 
evolved  from  the  cultures,  and  may  also  be  recognized 
in  the  lesions.  It  stains  readily  with  practically  all  of 
the  aniline  dyes  but  not  with  Gram's  stain. 

The  Bacillus  necrophorus  produces  disease  by  products 
that  it  elaborates  and  eliminates  into  the  tissue.  This 
microorganism  is  pathogenic  for  practically  all  animals; 
but  as  a  rule  it  is  only  a  secondary  invader,  the  tissue 
resistance  having  been  diminished  by  previous  disease 
process  or  by  injury.     Inoculations  of  cultures  of  the 


INFECTIOUS  DISEASES  209 

Bacillus  necrophorus  produces  necrosis,  or  abscess  forma- 
tion, in  cattle,  sheep,  swine,  and  horses. 

Source  of  infection. — The  Bacillus  necrophorus 
inhabits  the  digestive  tube  of  swine  and,  less  frequently, 
the  digestive  tube  of  other  animals;  therefore  the  micro- 
organism is  found  in  the  feces  of  practically  all  animals. 
Soil,  yards,  pens,  floors — in  fact,  practically  all  of  the 
surroundings — easily  become  contaminated  with  fecal 
matter,  and  the  disease  may  be  obtained  from  anything 
that  has  been  contaminated  with  feces.  Infection  is 
usually  indirect,  although  the  Bacillus  necrophorus  may 
be  transmitted  from  an  affected  to  a  healthy  animal  by 
contact, 

Channel  of  entrance. — This  infective  agent  may  be 
successfully  introduced  into  the  susceptible  swine  in  food 
or  drink  by  way  of  the  mouth,  upon  inhaled  dust  particles 
by  way  of  the  respiratory  organs,  or  it  may  be  introduced 
through  abrasions  of  the  skin,  and,  more  rarely,  into  the 
genital  organs  during  copulation. 

Lesions. — The  Bacillus  necrophorus  is  capable  of 
invading  practically  any  tissue  of  the  body,  and  the 
lesions  produced  so  closely  resemble  each  other  that  one 
general  description  will  suffice.  The  lesion  consists  of 
a  coagulation  necrosis,  the  necrotic  material  later  becom- 
ing caseated.  The  local  lesion  has  a  tendency  to  become 
larger,  due  to  the  infiltration  of  the  surrounding  tissue 
with  the  products  of  the  Bacillus  necrophorus.  The 
infection,  and  therefore  the  lesions,  may  occur  elsewhere 
in  the  body,  due  to  metastasis.  There  may  be  general 
emaciation  due  to  absorption  of  the  products  of  the 
Bacillus  necrophorus,  and  tissue  destruction. 

The  local  specific  lesion  is  a  sharply  circumscribed 
yellowish  or  brownish  area  containing  a  homogeneous, 
dry,  mealy,  or  cheese-like  substance  from  which  a  pungent 
and  disagreeable  odor  emanates.  Microscopic  examina- 
tion of  a  section  of  one  of  these  areas  reveals  a  central 
mass  of  tissue  debris  composed  of  disintegrating  and  de- 
stroyed cells  which  do  not  stain.  Surrounding  the 
necrotic  area  is  a  zone  made  up  of  leukocytes,  damaged 


210  SWINE  DISEASES 

tissue  cells,  and  considerable  numbers  of  Bacillus  necro- 
phorus  filaments  arranged  in  bundles.  The  surrounding 
tissue  evidences  a  severe  reaction  by  hyperemia,  and  the 
presence  of  large  numbers  of  leukocytes  and  a  few  Bacilli 
necrophorus.  "••■> 

Necrobacillosis  assumes  many  different  forms,  the 
most  common  of  which  are  necrotic  stomatitis,  enteritis, 
rhinitis,  pneumonia,  hepatitis,  splenitis,  vaginitis,  and 
dermatitis. 

Necrotic  Stomatitis 

Necrotic  stomatitis  is  probably  the  most  common 
form  of  necrobacillosis.  It  is  of  frequent  occurrence  in 
suckling  pigs. 

Lesions  and  symptcms. — The  inflamma'tion  usually 
begins  at  the  margins  of  the  gums.  The  successive 
changes  in  the  affected  areas  are  as  follows.  The  surface 
is  red  or  blui-sh  red,  becomes  tumefied,  is  very  sensitive, 
and  bleeds  easily.  Two  or  three  days  later  the  area  be- 
comes yellowish  white  or  even  brown  in  color  and  of  a 
mushy  consistency,  and  usually  sloughs,  leaving  an 
eroded  surface  which  is  covered  by  a  coagulated  necrotic 
tissue  and  appears  as  a  diphtheritic  membrane.  The 
surrounding  tissue  becomes  red,  tumefied,  and  sensitive. 
The  disease  process  gradually  extends  and  ultimately 
becomes  confluent,  forming  large  eroded  areas.  A 
similar  process  frequently  affects  the  lips  simultaneously. 

The  affected  pigs  frequently  attempt  to  nurse,  but  the 
gums  are  so  sensitive  that  they  obtain  little  nourishment. 
Pigs  may  transmit  the  disease  to  the  teats  of  their  mother 
by  nursing.  There  is  salivation  and  champing  of  the 
teeth.  Upon  inspection  the  foregoing  lesions  are 
observed  and  a  peculiar  disagreeable  odor  is  also  noted 
which  may  permeate  the  air  and  be  recognized  at  a 
considerable  distance.  As  the  disease  progresses  the 
discharged  saliva  becomes  bloody  and  contains  shreds  of 
tissue. 

1^'  I  The  course  of  this  disease  varies  from  a  few  days  in 
the  acute  form  to  several  weeks  in  the  chronic  form. 


INFECTIOUS  DISEASES  211 

Diagnosis. — The  identification  of  necrotic  stomatitis 
is  not  difficult  if  the  typical  necrotic  lesions  are  observed 
and  the  peculiar  offensive  odor  is  recognized. 

Treatment. — In  the  early  stages  the  treatment  of 
the  cases  may  be  successful,  but  in  the  advanced  stages 
the  disease  usually  proves  fatal  regardless  of  treatment. 
The  most  successful  treatment  consists  in  washing  the 
oral  cavity  and  applying  upon  the  eroded  areas  one- 
percent  solutions  of  silver  nitrate  or  three-  to  five-percent 
solutions  of  zinc  chlorid.  Local  treatment  should  be 
repeated  frequently. 

Necrotic  Enteritis 

This  is  frequently  a  sequel  to  necrotic  stomatitis,  the 
infection  passing  along  the  digestive  tube  in  the  patches 
of  sloughed  necrotic  tissue  or  directly  from  the  intestinal 
content.  Necrotic  enteritis  is  relatively  common  in 
swine.     It  frequently  accompanies  hog  cholera. 

Lesions. — The  lesions  of  necrotic  enteritis  are  most 
common  in  the  mucous  membrane  of  the  intestine  near 
the  ileocecal  orifice.  The  lesion  is  very  similar  to  that 
of  necrotic  stomatitis,  except  that  here  the  necrotic  tissue 
usually  remains  intact  and  becomes  coagulated  and 
mealy  or  caseous.  This  adhering  pseudomembrane  may 
occur  in  small,  scattered,  circumscribed  areas,  or  prac- 
tically the  entire  mucous  membrane  may  be  involved. 
Microscopically  the  surface  epithelia  in  the  affected  areas 
are  found  disintegrated  and  commingled  with  the  coagu- 
lated debris  upon  the  mucous  surface. 

Symptoms. — This  condition  frequently  exists  to  a 
limited  degree  without  manifestation  of  any  symptoms. 
In  the  cases  where  the  lesions  are  more  extensive  there  is 
indigestion,  coHcky  pains,  and  diarrhea.  Later  the  appe- 
tite may  be  diminished  or  the  desire  for  food  may  cease; 
the  animals  become  unthrifty,  emaciated,  and  weak. 
The  course  varies  with  the  intensity  of  the  disease;  it 
may  run  a  rapid  course  or  it  may  become  chronic.  It  is 
rarelv  fatal. 


212 


SWINE  DISEASES 


Treatment. — Proper  dieting  and  the  provision  of 
good  sanitary  quarters  must  first  be  considered.  The 
use  of  castor  oil  to  clean  the  bowel  of  offending  material 
is  a  good  practice.  Intestinal  antiseptics,  too,  may  be 
used  to  good  advantage. 

Necrotic  Rhinitis 

This  condition  is  usually  associated  with  necrosis  of 
the  snout  and  frequently  also  of  the  lips,  and  is  of  rather 
common  occurrence  in  small  pigs.  It  is  one  of  the  con- 
ditions that  constitutes  the  disease  called  sniffles.  Sniffles 
also  includes  catarrhal  rhinitis,  particularly  those  cases 
in  which  deformity  of  the  snout  and  nasal  cavities  occurs, 


Fiff.    34.— NECKOBACILLOSIS. 

and  those  cases  of  rickets  in  which  there  is  involvement 
of  the  nasal  and  facial  bones,  causing  more  or  less 
deformity.  ? 

Lesions. — Necrobacillosis  of  the  schneiderian  mucous 
membrane  and  the  snout  is  characterized  by  the  same 
lesions  that  are  characteristic  of  necrotic  stomatitis, 
except  that  here  bone  tissue  is  frequently  involved, 
resulting  in  fibrinous  proliferation  and  deformity  of  the 
parts. 

Symptoms. — The  affected  animals  have  a  tendency 
to  root  considerably  in  their  food,  but  they  eat  little. 
The  characteristic  symptom  consists  of  a  peculiar  blow- 
ing noise.     The  animals  sneeze,  and  occasionally  expel 


INFECTIOUS  DISEASES  213 

bloody  material  containing  shreds  of  tissue.  The  snout 
becomes  enlarged  and  the  face  bulging,  this  condition 
frequently  being  called  an  elephant  head. 

Treatment. — It  is  not  possible  to  efficiently  treat 
these  cases  because  of  the  difficulty  of  applying  medica- 
ments to  the  lesion  and  further  because  of  the  destructive 
changes  in  the  bones  of  the  nose  and  face. 

Necrotic  Pneumonia 

Necrotic  pneumonia  is  frequently  an  associated  con- 
dition of  necrotic  rhinitis,  the  infection  taking  place  by 
the  inhalation  of  necrotic  particles  from  the  nose. 

Lesions. — The  same  general  coagulation  necrosis 
type  of  lesions  that  characterizes  necrobacillosis  are 
observed  also  in  necrotic  pneumonia. 

Symptoms. — Manifestations  of  the  disease  are  similar 
to  those  of  croupous  pneumonia,  though  evidence  of  septic 
intoxication  is  more  pronounced  than  in  the  latter.  The 
very  offensive  odor  of  the  expired  air  characterizes  pul- 
monary necrobacillosis. 

Treatment. — Treatment  other  than  providing  good, 
nourishing  food  and  sanitary  surroundings  is  of  little 
or  no  avail. 

Necrotic  Hepatitis 

Hepatic  necrobacillosis  is  not  of  common  occurrence, 
but  some  cases  have  been  observed.  It  is  usually  sec- 
ondary to  necrotic  enteritis,  the  infection  passing  through 
the  portal  system  and  metastasizing  in  the  liver. 

Lesions. — The  lesions  consist  of  sharply  circum- 
scribed grayish-white  areas  varying  in  size  from  that  of  a 
pinhead  to  a  silver  dollar.  These  areas  may  be  sur- 
rounded by  a  fibrous  capsule.  The  density  or  consistency 
of  the  lesion  depends  upon  its  age.  It  may  be  of  the 
same  consistency  as  the  surrounding  liver,  it  may  be  dry 
and  mealy,  or,  if  the  animal  recovers,  it  may  become 
calcareous.  These  areas  may  not  cause  any  irregularity 
in  the  size  or  shape  of  the  liver  or  the  lesion  may  assume 
the  nodular  form,  the  nodules  projecting  from  the  surface 
of  the  liver.     The  surface  nodules  have  a  raised  border 


214  SWINE  DISEASES 

and  a  depressed  center,  and  are  quite  characteristic  in 
appearance. 

SymptCIH^. — No  definite  symptoms  have  been  at- 
tributed to  hepatic  necrobacillosis  other  than  general 
digestive  derangement.  These  cases  are  diagnosed  at 
autopsy. 

Treatment. — The  location  of  the  lesions  and  the 
nature  of  the  process  practically  eliminate  the  possibility 
of  successful  treatment. 

Necrotic  Spleenitis 

Splenic  necrosis  is  a  rather  common  condition  in 
swine.  It  may  be  caused  by  other  agencies  than  the 
Bacillus  necrophorus,  but  from  investigations  thus  far 
conducted  it  appears  that  the  most  frequent  cause  of 
necrosis  of  the  spleen  is  the  Bacillus  necrophorus.  This 
condition  is  commonly  associated  with  the  use  of  a 
contaminated  hog-cholera  virus.  The  infection  is  carried 
in  the  blood  to  the  spleen. 

Lesions. — The  necrotic  centers  in  the  spleen  are 
usually  encapsulated,  the  density  of  the  capsule  varying 
with  the  length  of  duration  of  the  process.  As  a  rule, 
the  centers  are  in  the  form  of  nodules.  They  are  of  a 
grayish-white  color  and  usually  have  a  depressed  center 
and  a  raised  border.  In  size  these  foci  vary  from  masses 
half  an  inch  in  diameter  to  irregular  masses  from  one  to 
three  inches  in  diameter.  There  may  be  only  a  few 
centers,  but  usually  there  are  many;  in  some  instances  so 
numerous  are  they  that  it  is  difficult  to  identify  any  nor- 
mal splenic  tissue.  The  non-encapsulated  lesions  are 
dirty-white  centers  and  give  the  appearance  of  having 
been  painted  in  the  splenic  tissue. 

Symptoms  are  indistinct,  and  treatment  cannot  be 
applied. 

Vaginal  Vulvar  and  Preputial  Necrosis 

Necrotic  vaginitis  and  vulvitis  occurs,  but  is  not 
prevalent.  Infection  probably  gains  entrance  through 
abrasions  produced  at  the  time  of  parturition  or  copula- 
tion or,  more  rarely,  by  means  of  accidental  traumatic 


INFECTIOUS  DISEASES 


215 


wounds.  The  lesions  consist  of  tumefaction,  redness, 
and  sensitiveness,  followed  by  necrosis.  The  necrotic 
tissue  may  become  desiccated  and  slough,  or  it  may  be 
converted  into  a  mushy  mass.  The  erosion  of  the  vulva 
may  destroy  the  vulvar  tissue  and  even  the  anal  tissue. 
Dense  masses  of  fibrous  tissue  usually  develop  in  the 


x-.a^ 


^^ 


Fig.  35. — FAT   XECK081S    (Omentum). 
A.  Xorinal  fat.     B.  areas  of  necrosis. 


perinecrotic  zone,    which   later  cicatrizes   and  produces 
various  distortions  of  the  vulvo-anal  structures. 

Infection  of  the  prepuce  may  gain  entrance  through 
abrasions  produced  by  inflammation  that  has  resulted 
from  irritation  from  urine,  screw  worms,  or  similar 
causes.  Infection  may  also  be  favored  by  traumatic 
injuries  of  various  kinds.     The  lesions  are  of  the  same 


i.6  SWINE  DISEASES 

general  nature  as  those  observed  in  vulvitis.  The  prepuce 
occasionally  becomes  entirely  destroyed,  and  sometimes 
the  penis  becomes  involved. 

The  vulvar  and  preputial  lesions  sometimes  interfere 
wilh,  and  even  inhibit  urination,  resulting  in  retention  of 
urine.  In  such  cases  in  the  male  the  sheath  may  become 
enormously  distended  with  urine. 

Treatment. — Treatment  is  confined  to  the  local 
japplication  of  some  penetrating  disinfectant.  Those 
lesions  that  become  necrotic  are  removed  in  order 
that  the  disinfectant  may  have  free  access  to  the  invaded 
tissue.  Adhesions  and  other  conditions  that  obstruct  the 
urine  should  be  corrected,  at  least  temporarily,  in  order 
that  the  urine  may  be  voided  and  thus  uremic  poisoning 
prevented. 

Necrotic  Dermatitis 

Necrotic  dermatitis,  aside  from  the  type  affecting 
the  lips,  vulva,  and  prepuce,  is  sometimes  encountered. 
It  is  of  most  frequent  occurrence  in  young  pigs,  and  affects 
any  portion  of  the  body.  Infection  of  the  Bacillus 
necrophorus  into  the  skin  is  probably  possible  only  through 
abrasions  and  wounds. 

Lesions. — The  lesions  arc  practically  the  same  as  in 
other  superficial  necrobacillosis.  Not  infrequently  large 
areas  slough,  leaving  irregular  denuded  surfaces.  This 
condition  is  frequently  fatal,  particularly  in  those  cases 
having  extensive  infection  where  absorption  of  the  prod- 
ucts is  suflBcient  to  insure  systemic  disturbance. 

Treatment. — Treatment  consists  of  removing 
necrotic  tissue  and  applying  some  antiseptic  that  will 
readily  penetrate  the  infected  area.  The  treatment 
must  be  persistent,  as  relief  cannot  be  obtained  from 
one  application. 

Unusual  Forms  of  Necrobacillosis 

Necrobacillosis  sometimes  occurs  in  the  various 
structures  of  the  eye.  This  is  a  serious  condition,  as  the 
agents  used  in  combating  the  Bacillus  necrophorus  have 
to  be  used  in  such  concentration  that  they  are  injurious 


INFECTIOUS  DISEASES  217 

to  the  ej^e.  The  usual  outcome  of  ocular  necrobacillosis 
is  destruction  of  the  eye,  and  if  both  eyes  are  involved 
the  animal  becomes  blind  and  usually  has  to  be  destroyed. 

Necrobacillosis  as  a  sequel  of  castration  has  been 
previously  discussed  (See  p.  120). 

Necrobacillosis  is  a  disease  that  may  affect  practically 
any  and  all  tissues  of  swine  and  is  of  considerable  economic 
importance.  The  most  common  forms  of  the  disease 
are  necrotic  stomatitis  and  enteritis,  and  necrosis  of  the 
sheath. 

TUBERCULOSIS 

Tuberculosis  is  a  specific  infective  disease  caused  by 
the  tubercle  bacillus  and  characterized  by  the  formation 
of  tubercles. 

History. — Tuberculosis  has  been  recognized  from 
the  remotest  time  in  the  history  of  man  as  a  prevalent 
disease  of  mankind.  In  1689  the  tubercle  was  identified 
by  Morton  as  the  typical  lesion  of  tuberculosis.  Various 
investigators  have  given  additional  knowledge  on  the 
subject  of  tuberculosis.  In  1865  Villemin  proved  the 
infectiousness  of  the  disease,  while  Koch  discovered  the 
tubercle  bacillus  in  1882,  thus  establishing  firmly  the 
theory  of  the  infectiousness  of  tuberculosis.  The  study 
of  tuberculosis  has  been  advanced  and  its  recognition 
clinically  has  been  made  possible  by  the  use  of  tuberculin 
which  was  discovered  by  Koch  in  1890.  In  1901  he 
startled  the  scientific  world  by  announcing  at  the  tubercu- 
losis congress  in  London  that  human  and  bovine  tuber- 
culosis were  separate  and  distinct  diseases,  a  statement 
that  was  responsible  for  the  organization  of  different 
scientific  bodies  that,  after  careful  investigation,  reported 
that  although  there  may  be  some  slight  difference  between 
the  tubercle  of  human  and  bovine  origin,  the  disease 
produced  is  the  same  and  that  the  disease  is  inter- 
transmissible  between  animals  and  man. 

Occurrence. — Tuberculosis  is  becoming  very  preva- 
lent among  swine.  This  is  due  to  the  fact  that  the  dairy- 
ing industry  is  becoming  more  extensive  and  the  by  prod- 


218  SWINE  DISEASES 

ucts  of  milk  are  used  for  swine  feed.  A  relatively  large 
percentage  of  dairy  cattle  istuberculous,  and  the  infection 
gains  entrance  to  the  milk  on  filth  that  is  contaminated 
with  infected  discharges,  such  as  saliva  and  feces.  The 
organism  may  also  be  eliminated  direct  from  the  mammary 
gland  into  the  milk. 

Swine  from  some  sections  of  the  United  States  have 
been  found  by  experience  to  be  so  extensively  tuberculous 
that  some  packers  will  buy  them  only  subject  to  post- 
mortem inspection. 

In  Germany  from  2.46  to  2.81  percent  of  swine 
slaughtered  at  abattoirs  were  condemned  on  account  of 
tuberculosis.  The  disease  is  very  prevalent  in  Belgium, 
France,  Norway,  and  Sweden,  and  porcine  tuberculosis 
is  a  common  disease  in  the  British  Isles.  According  to 
the  annual  report  of  the  Bureau  of  Animal  Industry  for 
1911,  29,920,260  carcasses  of  swine  were  inspected  in 
abattoirs,  and  of  that  number  31,517  carcasses  and  870,361 
parts  were  condemned  on  account  of  tuberculosis.  The 
disease  is  becoming  more  extensive  in  swine  in  the  United 
States  and  should  receive  more  consideration  than  it 
does,  for  the  economic  loss  annually  is  enormous. 

Etiology. — The  cause  of  tuberculosis  is  the  tubercle 
bacillus  or  the  Bacillus  of  Koch.  It  is  a  rod-shaped 
organism  from  1.5  to  4  microns  long  and  .3  to  .5  micron 
in  width,  and  is  usually  curved  or  slightly  bent.  It 
may  contain  granules  or  the  body  may  be  uniform.  It 
is  nonmotile  and  does  not  form  spores.  This  organism 
is  covered  with  a  waxlike  substance  which  renders  it  more 
difficult  to  stain  than  ordinary  bacteria,  but  after  the 
organism  has  been  stained,  which  can  be  accomplished 
by  applying  steaming  carbolfuchsin  for  five  minutes,  it 
retains  the  stain  even  when  subjected  to  the  action  of 
acids;  for  this  reason  it  has  been  called  an  acid-fast 
bacterium.  It  is  an  aerobe,  and  grows  with  relative 
slowness.  It  grows  luxuriantly  in  egg  albumen  culture 
medium,  and  fairly  well  on  glycerine  agar  and  in  glycerine 
bouillon.  Tubercle  bacilli  from  different  sources  manifest 
different  cultural  characteristics,  and  on  this  basis  some 


PLATE  III. 


Fig.  1 


Fig.  2 


Fig.  1.    A  typical  tuberculous  liver. 

Fig.  2.     Vertebrae  showing  tuberculous  bone  lesions. 


INFECTIOUS  DISEASES  219 

have  claimed  four  varieties  of  tubercle  bacilli,  namely, 
human,  bovine,  avian,  and  reptilian.  The  bovine  and 
human  types  have  been  encountered  in  swine. 

The  tubercle  bacilli  are  very  resistant  to  external 
injurious  influences.  This  resistance  is  probably  due  to 
the  waxy  coat  they  possess.  Direct  sunlight  destroys 
them  when  freely  exposed  for  twenty  to  thirty  minutes, 
but  they  retain  their  vitality  and  virulence  for  from  ten 
to  twenty  days  when  exposed  to  diffuse  daylight.  When 
desiccated  and  not  exposed  to  light  they  may  retain 
their  virulence  for  four  months  or  even  longer.  In 
decomposing  tubercular  tissues  they  remain  virulent  for 
a  long  time.  In  milk  they  retain  virulence  for  ten  days. 
Dry  heat  at  212  degrees  Fahrenheit  destroys  them  in  one 
hour;  moist  heat  at  the  boiling  temperature  will  destroy 
them  in  fifteen  minutes.  They  are  also  destroyed  by 
chemical  disinfectants,  the  length  of  time  for  exposure 
depending  upon  the  concentration  of  solution  and  the 
nature  of  the  tissue  or  discharge  incorporating  the  bacilli. 
Gastric  juice  does  not  destroy  the  tubercle  bacilli,  and 
bile  has  little  or  no  injurious  effect  upon  them. 

The  inoculation  of  healthy,  susceptible  animals  with 
virulent  bacilli  produces  tuberculosis,  the  extent  of  the 
lesions  produced  depending  upon  the  virulence  of  the 
bacilli  injected  and  upon  the  resistance  of  the  inoculated 
animal. 

Source  of  infection. — Tubercule  bacilli  are  elimi- 
nated from  the  affected  animals,  at  least  when  there  are 
open  lesions  in  organs,  the  secretions  or  excretions  of 
which  pass  to  the  outside  world.  Thus  the  tubercle 
bacilli  are  eliminated  in  the  feces  from  animals  having 
tubercular  ulcers  of  the  intestinal  mucosa.  Open  tu- 
berculous lesions  of  the  respiratory  tract  would  permit  of 
the  elimination  of  the  tubercle  bacilli  in  the  discharge 
from  the  air  tubes  and  also  in  the  feces,  for  the  chances 
are  that  the  pharynx  would  become  contaminated  by 
the  pulmonary  or  tracheal  discharge  and  this  infection 
would  be  carried  with  food  or  drink  and  ultimately  pass 
from  the  body  in  the  feces.     Tubercle  bacilli  from  lesions 


220  SWINE  DISEASES 

in  the  liver  or  pancreas  may  also  be  eliminated  in  the 
feces. 

Tubercle  bacilli  from  open  tubercular  lesions  of  the 
urogenital  organs  are  eliminated  in  the  urine,  seminal 
fluid,  or  other  discharges  from  these  organs.  Infection  is 
directly  eliminated  from  open,  cutaneous,  tuberculous 
lesions,  and  tubercle  bacilli  may  be  eliminated  in  the 
milk,  especially  if  tuberculous  lesions  exist  in  the  mammary 
gland. 

The  dissemination  of  tubercle  bacilli  in  the  body  and 
the  possibility  of  their  elimination  through  any  channel 
is  facilitated  by  leukocytes.  Thus  tubercle  bacilli  in  the 
lung  may  be  incorporated  and  retained  by  leukocytes 
that  are  later  eliminated  by  the  mammary  cells,  and  the 
milk  become  infected  even  though  the  mammary  gland 
contain  no  tuberculous  lesions. 

From  the  foregoing  it  is  evident  that  any  of  the  dis- 
charges of  tuberculous  animals  may  contain  the  tubercle 
bacilli.  In  the  United  States  and  in  practically  all  other 
countries  tuberculosis  of  cattle  is  prevalent,  particularly 
among  cattle  used  for  dairy  purposes. 

The  most  frequent  source  of  porcine  tuberculosis  is 
from  tuberculous  cattle.  Swine  become  infected  from 
infected  cow's  milk,  feces,  nasal  discharges,  and  the  car- 
casses of  tuberculous  cattle  that  are  given  them  for  food 
A  limited  number  of  swine  become  infected  from  garbage 
that  contains  the  human  tubercle  bacilli.  This  has  been 
especially  observed  in  swine  fed  upon  garbage  from  tuber- 
culosis sanitaria,  or  hotels.  An  occasional  case  of  uterine, 
ovarian,  or  testicular  tuberculosis  is  the  result  of  direct 
infection  by  copulation.  It  is  possible  that  infection 
may  be  transmitted  in  the  exhaled  air  from  infected  to 
healthy  swine. 

Channels  of  entrance. — The  most  frequent  channel 
of  entrance  of  the  tubercle  bacilli  in  swine  is  the  digestive 
tube,  the  infection  being  introduced  in  food  or  water. 
An  occasional  case  may  become  infected  by  the  inhalation 
of  the  bacilli  and  by  direct  transmission  through  the  geni- 
tal organs.     Mammary    tuberculosis  may  be  the  result 


[NFECTIOUS  DISEASES  221 

of  cutaneous  infection  or  it  may  be  transmitted  from 
elsewhere  in  the  body. 

The  transmission  of  the  tubercle  bacilH  from  the 
mother  to  the  fetus  is  possible  but  it  is  of  rare  occurrence. 
But  a  weakened  condition  or  susceptibility  to  the  disease 
may  and  frequently  is  transmitted  from  the  mother  to 
the  fetus. 

Lesions. — The  typical  initial  lesion  of  tuberculosis  is 
the  tubercle  which  has  been  aptly  defined  as  a  nonvascular 
nodule  composed  of  leukocytes,  endothelial,  giant 
and  connective  tissue  cells,  with  a  tendency  for  the 
central  part  of  the  nodule  to  undergo  necrosis.     There 


Fig.  26.— TUBERCUI.OSIS  OF  THE  TONGUE. 
A.  Normal  muscle.     B.  tuberculous  lesions.     This   is  a  rare  condition 
in   8 nine. 

may  be  slight  variation  in  the  tubercle  in  different  ani- 
mals, due  to  variation  of  susceptibility  of  the  animal  and 
variation  of  the  virulency  of  the  infecting  bacilli.  The 
typical  lesion  may  also  be  materially  modified  by  second- 
ary lesions.  Tuberculous  lesions  may  occur  in  any  tissue 
or  organ,  but  Ij^mphoid  tissue  is  most  frequently  affected. 
The  tubercle  bacilli  and  their  products  are  the  causa- 
tive factors  in  the  formation  of  a  tubercle.  Having 
lodged  in  a  tissue  favorable  for  their  growth  and  develop- 
ment, the  bacilli  begin  to  multiply  and  to  eliminate 
products  that  stimulate  the  surrounding  connective  tissue 
and  endothelial  cells  to  increase  in  number,  and  at  the 


222 


SWINE  DISEASES 


same  time  exert  a  positive  chemotactic  action  upon  the 
leukocytes.  In  swine  there  is  a  very  marked  chemotactic 
action  and  limited  stimulation  of  connective  tissue. 
The  typical  porcine  tuberculosis  tubercle  is  largely  com- 
posed of  leukocytes  and  has  little  fibrous  tissue. 

Tubercles  grow  because  of  the  increased  accumulation 
of  leukocytes  and  the  formation  of  a  small  quantity  of 
fibrous  tissue.  The  tubercle  contains  no  blood  vessels; 
that  is,  it  is  nonvascular,  although  in  the  early  stages 
there  may  be  a  hyperemic  zone  around  the  tubercle. 
This  hyperemic  zone  is  the  result  of  irritation  in  the  tissue, 


Fig.   27.— TUBEKCULOSIS   OF   THI5   SKIN. 
A.    The    skin    showing   caseo-calearous    lesions.     B.    subcutaneous   fat. 
C.  muscle. 


the  tubercle  formation  causing  a  tissue  reaction.  As  the 
tubercle  becomes  larger,  due  to  the  accumulation  of 
leukocytes  on  the  margin,  the  central  part  begins  to 
degenerate.  , 

Porcine  tubercular  lesions  are  characterized  by  en- 
largement of  lymphatic  glands,  the  formation  of  tubercles 
of  variable  sizes  in  or  upon  serous  membranes  and  within 
the  substance  of  glandular  organs,  bones,  and  other 
connective  tissues.  The  tubercles  produce  increased 
density  of  invaded  soft  tissues  and  are,  therefore,  easily 
detected  except  in  very  recent  infection.  The  tubercular 
nobules  in  the  early  stages  present  about  the  same  color 
as  the  surface  of  the  tissue  invaded.     In  sectioning  the 


INFECTIOUS  DISEASES  223 

tubercle  the  central  portion  is  caseous  and  slightly  yellow, 
or  fibrous  and  white.  Sometimes  there  is  a  combination 
of  both  conditions,  and  occasionally  the  tubercles  contain 
calcareous  granules.  The  central  portion  of  porcine 
tubercles  rarely  contains  liquefied  necrotic  tissue. 

Microscopically,  porcine  tubercular  lesions  are  always 
cellular  in  the  beginning,  the  cellular  tubercles  being 
fairly  constant  in  structure,  regardless  of  the  tissue  in 
which  they  occur.  The  center  is  at  first  represented  by 
a  mass  of  lymphoid  cells,  the  other  cellular  elements 
occurring  as  the  tubercle  develops. 

Necrosis,  or  fibrosis,  succeeds  the  cellular  stage  in 
the  porcine  tubercular  lesion.  Necrosis  of  tubercles  is 
probably  the  result  of  the  activity  of  virulent  bacteria  or 
the  low  resistance  of  the  infected  animal.  The  necrotic 
center  may  be  surrounded  by  a  cellular  zone  (lymphoid 
and  endothelial  cells),  or  it  may  be  surrounded  by  fibro- 
blasts. The  necrotic  material  is  invariably  caseated  and 
later  becomes  calcified. 

Fibrous  lesions  vary  from  the  formation  of  small 
quantities  of  fibrous  tissue  to  dense  fibrous  centers. 
They  are  probably  produced  by  bacteria  of  low  virulence, 
or  occur  in  animals  having  a  marked  resistance.  The 
central  portion  of  the  fibrous  lesion  may  become  calcified. 

The  so-called  arbor  vitae  gland  is  a  fibrous  center  in 
which  the  fibrous  tissue  is  arranged  similarly  to  the  trunk 
and  branches  of  a  tree,  hence  the  name.  In  the  hog, 
this  lesion  is  observed  in  the  cer\'ical  lymph  nodes.  The 
Bacterium  tuberculosis  has  been  demonstrated  in  about 
thirty  per  cent  of  arbor  vitse  glands. 

The  lesions  of  porcine  tuberculosis  are  in  brief  either 
cellular,  necrotic,  and  calcified  tubercles,  or  cellular, 
fibrous,  and  calcified  tubercles.  The  lesion  is  always 
nonvascular,  as  in  other  animals. 

Tubercular  lesions  are  most  common  in  the  digestive 
\4scera.  The  hver  and  spleen  frequently  contain  caseous 
nodules. 

Pulmonary  porcine  tuberculosis  manifests  itself  either 
by  a  few  or  many  cheesy  foci  or  by  a  few  large  centers. 


224  SWINE  DISEASES 

There  may  be  a  general  caseous  pneumonia  associated 
with  more  or  less  pleurisy. 

Tubercular  involvement  of  the  nervous  tissue  occurs 
in  swine,  but  is  relatively  rare.  One  case  has  been  ob- 
served in  which  a  tubercular  center  occurred  in  the 
cerebral  tissue.  Tuberculosis  of  the  meninges  may  be 
local  and  circumscribed  or  diffuse  and  quite  general. 

Osseous  tuberculosis  is  of  common  occurrence  in 
swine.     It  is  found  especially  in  the  vertebrae. 

Symptoms. — Tuberculosis  is  essentially  a  chronic 
disease.  The  onset  is  usually  so  insidious  that  no  ab- 
normality is  suspected,  and  the  usual  clinical  examination 
of  swine  is  not  suflBcient  to  predicate  a  diagnosis  because 
the  symptoms  are  so  indistinct.  Lymph-gland  involve- 
ments result  in  tumefaction.  The  enlarged  glands  are 
not  pathognomonic  of  tuberculosis. 

Tubercular  invasion  of  the  digestive  organs  produces 
indigestion.  The  digestive  derangements  develop  slowly 
and  usually  only  in  young  pigs.  They  become  unthrifty 
and  emaciated  as  the  disease  progresses. 

Pulmonary  tuberculosis  is  evidenced  by  a  dry,  short, 
suppressed  cough  and  by  some  difficulty  of  breathing. 
The  cough  becomes  more  aggravated,  and  the  animals 
become  weak  and  thin  and  have  a  rough  coat. 

Tuberculosis  of  the  brain,  or  meninges,  is  not  common 
and  the  symptoms  evidenced  will  depend  upon  the  loca- 
tion of  the  lesion. 

Osseous  tuberculosis  is  associated  with  interference 
of  locomotion  and  tumefaction  of  the  affected  bone. 

The  length  of  the  course  of  tuberculosis  is  variable- 
In  young  pigs  it  may  "produce  fatal  termination  in  from 
two  to  three  months  after  the  onset.  Older  swine  rarely 
die  of  tuberculosis,  as  the  disease  assumes  a  chronic  form 
in  them  and  they  are  usually  marketed  before  the  dis- 
ease has  manifested  itself  clinically. 

Diagnosis.— The  clinical  diagnosis  of  this  disease  is 
practically  impossible  without  the  use  of  the  tuberculin 
test.  The  lesions  may  be  identified  and  the  disease  can 
therefore  be  recognized  by  autopsy. 


PLATE  IV, 


Fig.  1 


Fig.  2 


Fig.  1.  Spleen  showing  calcified  tubercles  sur- 
rounded by  hyperemic  margins. 

Fig.  2.  Lung  showing  areas  of  normal  tissue,  areas  of 
red  hepatization  and  caseo-calcareous,  tubercular  areaii 


INFECTIOUS  DISEASES 


225 


The  intradermal  tuberculin  test  is  most  applicable  to 
swine.  This  test  is  made  by  the  injection  into  the 
dermis  at  the  base  of  the  ear  of  from  three  to  five  minims 
of  ordinary  tubercuhn.*  The  reaction  consists  of  a 
dense  swelling  at  the  point  of  injection  and  becomes 
most  prominent  on  the  second  or  third  day  after  injection. 


4 


J 


^'^ 


Fiff. 


28.— TUBEBCrLOSIS   OF   THE   PLEURA. 

A.   Kib.     B.  masses  of  tubercles. 


The  subcutaneous  tuberculin  test  may  be  used,  but 
it  is  not  as  applicable  to  swine  as  it  is  to  cattle.  The 
ophthalmic  test  may  also  be  employed  in  swine. 

Microscopic  examination  may  be  made  of  the  various 
discharges   for  the  purpose   of   identifying   the   tubercle 

♦The  Bureau  of  Animal  Industry  have  issued  an  order  that  all  swine  used  for  tail 
bleeders  in  serum  production  must  be  tested  with  especially  prepared  intradermal 
tuberculin.  The  object  of  this  order  is  not  clear,  as  the  ordinary  tuberculin  is  as 
efficient  as  special  intradermal  tuberculin. 


226  SWINE  DISEASES 

bacilli.  In  making  this  test  it  must  be  remembered  that 
there  are  other  acid-fast  bacteria  and  further  that  the 
absence  of  tubercle  bacilli  in  the  preparations  examined 
is  not  positive  proof  of  the  absence  of  the  disease. 

Animal  inoculations  may  be  resorted  to,  particularly  in 
cases  in  which  no  tuberculin  test  has  been  made  and  there 
is  a  dispute  as  to  the  nature  of  the  lesions  found.    ^ 

Treatment. ^ — Curative  treatment  is  of  no  value  in 
porcine  tuberculosis.  The  only  rational  method  is  to 
sell  the  affected  swine  subject  to  the  post-mortem  inspec- 
tion findings.  In  this  way  some  value  will  be  obtained 
by  the  original  owner,  there  will  be  no  loss  to  the  packer, 
and  no  danger  to  the  consumer. 

Tuberculosis  is  a  preventable  disease  and  the  losses 
from  it  could  be  avoided,  or  at  least  materially  dimin- 
ished, by  proper  control  of  tuberculosis  in  cattle.  With 
our  present  farm  methods  the  eradication  of  poi'cine 
tuberculosis  cannot  be  accomplished  until  the  disease 
is  eradicated  in  cattle.  The  judicious  use  of  skimmed 
milk,  including  pasteurizing  milk  from  suspected  cows,  will 
materially  diminish  tuberculosis  in  milk-fed  swine. 
The  tuberculin  testing  of  steers  or  other  cattle  and  the 
elimination  of  all  reactors  will  prevent  the  introduction 
of  tuberculosis  in  swine  that  follow  cattle  in  the  feed  lots. 
Cooking  of  garbage  will  prevent  the  dissemination  of 
tuberculosis  to  swine.  Denver  garbage  is  cooked  and 
fed  to  swine,  the  infection  of  tuberculosis  and  hog 
cholera  as  well  is  thus  eliminated. 

OMPHALOPHLEBITIS,    PYEMIC   ARTHRITIS 
(NAVEL  ILL) 

This  is  an  acute  infectious  disease  of  recently  farrowed 
pigs  characterized  by  inflammation  of  the  umbilical 
tissues  and  suppurative  arthritis. 

Navel  or  joint  ill  has  prevailed  more  or  less  extensively 
since  the  dawn  of  history.  In  some  years  this  disease  is 
responsible  for  the  loss  of  a  large  percentage  of  the  young 
pigs    produced    in    certain    communities.     The    disease 


INFECTIOUS  DISEASES  227 

occurs  enzootically  and  as  an  epizootic,  sporadic  cases 
being  rare. 

Etiology.— This  condition  is  caused  by  infection,  but 
the  specific  exciting  cause  has  not  been  positively  identi- 
fied. The  Staphylococcus  pyogenes  aureus  has  been 
isolated  from  the  lesions  and  was  apparently  present  in 
practically  a  pure  culture.  A  Streptococcus  appears  to 
be  the  exciting  cause  in  some  cases,  and  in  other  cases  the 
colon  bacillus  or  some  of  its  derivatives  have  been  identi- 
fied. Bacillus  pyocyaneus  sometimes  causes  this  con- 
dition. The  young  animals  are  predisposed  to  the 
various  types  of  infection  by  filthy  surroundings  and 
improper  care.  Some  breeders  claim  that  if  the  sows 
are  permitted  to  farrow  in  clean  quarters,  and  are  main- 
tained and  fed  in  the  proper  way,  that  the  pigs  will  not 
contract  this  disease. 

There  is  evidence  of  the  transmission  of  the  disease 
in  utero  from  the  dam  to  the  foal  in  horses,  but  such 
e\'idence  has  not  been  obtained  in  swine. 

The  infection  gains  entrance  through  the  thrombi  in 
the  umbilical  ^'essels.  The  infecting  organisms  extend 
in  the  thrombus,  ultimately  reaching  the  blood  stream, 
by  means  of  which  they  are  disseminated  throughout 
the  body. 

Lesions. — The  manifestations  of  this  disease  are 
variable  and  depend  upon  the  number  and  virulency  of 
the  infecting  organism  and  their  location  in  the  body. 
The  typical  lesions  consist  of  omphalitis  and  suppurative 
arthritis.  Inflammation  of  the  umbilical  vessels  may  be 
limited  or  there  may  be  an  accumulation  of  pus,  the 
inflammation  being  a  typical  suppuration  and  abscess 
formation.  The  lesions  of  the  joints  are  variable. 
There  may  be  a  mild  synovitis  with  limited  or  extensive 
infiltration  and  tumefaction  of  the  structures  surrounding 
the  synovial  membrane,  in  which  cases  the  synovial  mem- 
brane is  injected  and  tumefied.  There  is  an  increased 
amount  of  fluid  and  it  will  be  turbid  and  perhaps  contain 
flakes  of  coagulated  material.  In  other  instances  the 
synovial  membrane  will  be  distended  with  accumulated 


228  SWINE  DISEASES 

pus  and  surrounding  tissues  may  also  be  infiltrated  with 
pus. 

Metastatic  abscesses  may  occur  in  various  organs,  as 
in  the  liver  and  spleen.  If  the  infection  extend  to  the 
bladder  there  will  also  be  a  purulent  cystitis. 

Symptoms. — The  symptoms  usually  appear  in  the 
first  week  of  life,  although  they  may  occur  in  the  second 
or  third  week  after  farrowing.  The  affected  pigs  will  be 
lame  and  indisposed  to  move.  On  examination  one  or 
more  of  the  articulations  are  found  to  be  swollen  and 
sensitive,  the  tarsal  joints  being  most  frequently  involved. 
There  may  be  diarrhea.  The  course  of  the  disease  is 
usually  brief,  the  pigs  as  a  rule  dying  on  the  second  or 
third  day. 

Treatment. — Curative  treatment  is  of  little  value. 
The  disease  may  be  prevented  by  providing  clean  pens 
and  keeping  them  clean  before  and  after  farrowing. 

SPASMS  OF  THE  DIAPHRAGM  (THUMPS) 

Thumps  is  a  condition  caused  by  violent  contractions 
of  the  diaphragm,  and  is  relatively  common  in  small  pigs. 

Etiology. — This  condition  is  apparantly  due  to  some 
interference  of  the  diaphragm,  and  is  usually  associated 
with  overloading  of  the  stomach  or  insufficient  exercise. 

Symptoms. — There  is  a  sudden  jerking  of  the  flanks. 
This  symptom  is  very  prominent  when  it  occurs  in  a  pig 
that  is  standing  quietly,  and  there  may  be  an  accompany- 
ing sound  that  is  quite  distinct.  There  is  an  irregularity 
in  the  frequency  of  the  contractions;  sometimes  they 
occur  in  rapid  succession,  followed  by  a  period  of  appar- 
ently a  normal  condition,  then  another  series  of  con- 
tractions. Exercise  and  a  full  stomach  aggravate  the 
condition.  The  pig  may  become  weak  and  emaciated. 
The  course  of  the  disease  varies  from  one  week  to  two  or 
three  months. 

Treatment. — Good  nourishing  food  and  plenty  of 
exercise  are  usually  sufficient  to  correct  spasms  of  the 
diaphragm.  Small  doses  of  from  two  to  three  drops  of 
tincture  of  opium,  administered  with  oil,  will  usually  give 
temporary  relief. 


INFECTIOUS  DISEASES  229 

Rabies 

Rabies  occurs  in  swine,  but  is  not  prevalent.  It  may 
occur  enzootically,  but  is  much  more  likely  to  affect  only 
one  animal,  or  few  animals  at  most,  in  any  one  locality. 

Etiology. — Rabies  is  caused  by  a  virus,  but  the  exact 
nature  of  this  virus  has  not  been  determined  more  than 
that  it  is  filterable.  Recently  it  has  been  successfully 
cultivated. 

Source  and  manner  of  infection. — The  usual 
source  of  rabies  in  swine  is  from  an  infected  animal, 
usually  a  dog.  Rabid  dogs  meandering  through  the 
country  occasionally  attack  swine,  biting  and  thus  infect- 
ing them. 

Lesions. — Gross  lesions  are  absent  in  s\\4ne  that  have 
died  of  rabies.  Foreign  substances  may  be  found  in  the 
stomach,  but  swine  have  a  habit  of  consuming  almost 
anything  and  therefore  foreign  bodies  in  the  stomach 
has  little  significance.  Microscopically,  ,  Negri  bodies 
are  found  in  the  cells  of  the  amnion  horn,  and  also  in  the 
cells  of  the  cerebellar  cortex.  These  bodies  are  the  same 
in  swine  as  in  other  animals. 

Symptoms. — Affected  sT\-ine  usually  become  excitable 
and  show  sexual  desire,  and  they  may  become  vicious 
and  attack  other  animals  or  man.  They  have  a  depraved 
appetite,  or  there  may  be  inappetence.  These  symptoms 
will  become  more  aggravated  for  two  or  three  days,  then 
the  animal  becomes  depressed  and  paralysis  of  various 
groups  of  muscles  appears.  The  affected  animals  may 
be  depressed  from  the  beginning,  soon  evidence  more  or 
less  of  paralysis,  and  finally  assume  a  comatose  state 
prior  to  death. 

Diagnosis. — Diagnosis  cannot  be  made  positive  by 
clinical  examination,  although  if  the  history  shows  con- 
tact with  a  rabid  animal  from  ten  days  to  four  weeks 
before  the  symptoms  appeared  one  could  diagnose  the 
case  as  suspected  rabies.  A  positive  diagnosis  can  be 
made  only  by  the  finding  of  Negri  bodies  by  microscopic 
examination,  or  the  reproduction  of  the  disease  by  inocu- 


230  SWINE  DISEASES 

lation  of  a  laboratory  animal  with  a  small  quantity  of 
the  brain  tissue  of  the  animal  in  question. 

Treatment. — Curative  treatment  has  always  been 
considered  futile.  Recently  the  use  of  quinine  has, 
according  to  reports,  given  good  results  in  cases  of  rabies 
in  dogs.  Other  investigators  have  failed  to  obtain 
beneficial  results  from  the  use  of  quinine  in  experimentally 
inoculated  cases  of  rabies.  If  valuable  animals  are 
known  to  have  been  bitten  by  a  rabid  dog  it  may  be 
given  the  Pasteur  treatment  and  thus  the  development 
of  the  disease  prevented. 

Foot  and  Mouth   Disease.      (Aphthae  Epizooticse) 

This  is  an  acute,  infectious,  transmissible  disease, 
primarily  affecting  cattle  and  sheep.  It  also  affects 
hogs,  goats,  more  rarely  horses,  dogs  and  other  animals. 

This  disease  is  quite  prevalent  in  some  European 
countries  and  it  has  appeared  in  the  United  States  on  six 
different  occasions:  In  1870,  1880,  1884,  1902,  1908  and 
1914. 

Etiology. — Foot-and-mouth  disease  is  produced  bj^ 
one  of  the  so-called  filterable  viruses,  which  up  to  the 
present  time  has  not  been  successfully  cultivated  outside 
of  the  animal  body.  The  virus  exists  especially  in  the 
serous  fluids  of  the  vesicles  in  the  mouth,  from  which  it 
gains  entrance  to  the  saliva  and  thus  to  the  soil  and  food 
from  the  salivary  secretions.  The  vesicular  lesions  are 
also  found  on  the  feet  and  thus  the  virus  also  gains  en- 
trance to  soil,  bedding  and  food,  from  which  other  animals 
can  easily  obtain  infection.  There  appears  to  be  little 
doubt  but  what  the  virus  is  eliminated  from  the  body  in 
all  excretions.  The  exact  length  of  time  the  virus  will 
retain  its  vitality  outside  of  the  animal  body  has  not 
been  determined,  but  it  has  been  observed  that  infection 
will  persist  in  buildings  that  have  not  been  disinfected 
for  several  months.  Some  outbreaks  of  this  disease 
have  been  apparently  traced  to  contaminated  hay,  that 
had  not  been  in  contact  with  diseased  animals  for  three 
months  or  more.     Thus  infection  mav  be  obtained  from 


INFECTIOUS  DISEASES  231 

food,  infected  premises,  hides  ami  in  the  varions  animal 
serums. 

In  the  1914  outbreak  in  the  United  States  several 
centers  of  infection  were  undoubtedly  established  through 
the  use  of  anti-hog  cholera  serum  that  had  been  made 
from  infected  hogs.  This  latter  source  is  of  considerable 
importance  and  should  entail  careful  inspection  upon  the 
part  of  the  government  employes  to  prevent  a  distri- 
bution of  the  disease  by  this  means. 

The  usual  channel  of  entrance  of  infection  is  through 
the  abrasion  of  the  buccal  mucous  membrane,  but  in 
hogs  the  infection  is  more  frequently  afiFected  through 
abrasion  of  the  skin  in  an  interdigital  space  or  around  the 
superior  part  of  the  hoof.  Such  abrasions  are  no  doubt 
of  very  common  occurrence  as  they  can  easily  be  produced 
by  stubs,  sticks  and  splinters  w  hich  are  very  common  in 
the  pens  where  hogs  are  maintained.  Infection  can  also 
be  introduced  upon  food  stuff,  especially  by  milk  from 
affected  cows  and  thus  gain  entrance  to  the  lesions  to 
abrasions  in  the  mouth,  and  as  before  stated  infection 
may  be  introduced  in  serum.  Some  authorities  are  of 
the  opinion  that  the  disease  may  be  carried  from  farm 
to  farm  by  birds  and  other  carrion  animals  and  thvis  an 
absolute  quarantine  should  be  maintained  on  all  infected 
premises. 

Lesions. — Foot-and-mouth  disease  assumes  two 
forms,  benign  and  malignant.  As  a  rule  hogs  are  not 
as  seriously  affected  with  this  disease  as  are  cattle,  a 
subacute  or  benign  form  being  most  prevalent  in  these 
animals.  The  principal  manifestation  of  this  disease 
consists  of  vesicles  which  develop  around  the  coronary 
band  and  in  the  interdigital  spaces.  One  or  more  feet 
may  be  involved  and  these  vesicles  vary  in  size  from  a 
grain  of  wheat  to  a  pea,  and  are  usually  of  short  duration. 
The  surface  of  the  epithelium  ruptures  and  later  des- 
quamates, leaving  a  denuded  surface.  The  surrounded 
surface  becomes  tumefied  and  hypersensitive.  Similar 
lesions  may  also  be  found  on  the  skin  of  the  snout  and 
less  frequently  upon  the  buccal  mucous  membrane.     If 


232  SWINE  DISEASES 

the  animals  are  maintained  in  clean  quarters  the  simple 
uncomplicated  lesions  will  heal  in  from  ten  days  to  three 
weeks.  If  the  animals  are  maintained  in  muddy,  filthy 
pens  secondary  infections  frequently  arise  and  the  hoof 
may  slough  and  the  animals  die  of  septic  infection.  \evy 
rarely  a  general  vesiculo-papular  eruption  may  occur  on 
large  areas  of  the  skin. 

Symptoms. — The  most  pronounced  symptoms  of 
foot-and-mouth  disease  in  hogs  consist  in  lameness;  the 
principal  lesions  being  found  on  the  feet.  The  animals 
have  a  disinclination  to  move  and  because  of  the  soreness 
tend  to  assume  a  decubital  position.  If  the  animals  are 
forced  to  move  they  will  probably  walk  upon  their  toes. 
The  lesions  in  various  stages  of  progress  may  be  observed 
at  this  time  by  inspection.  If  the  disease  is  of  a  virulent 
type  there  will  be  systemic  disturbances  consisting  of  rise 
of  temperature,  inappetence,  listlessness  or  dullness.  If 
the  buccal  mucous  membrane  is  involved,  there  will  be 
more  or  less  of  salivation  and  disinclination  to  eat. 

Course  and  Prognosis. — This  disease  usually  runs 
its  course  in  from  one  to  three  weeks,  although  it  may 
progress  for  a  longer  period.  The  disease  is  ordinarily 
not  fatal  if  uncomplicated  in  the  hogs,  although  the 
financial  value  of  the  animals  is  considerably  depreciated 
because  of  the  fact  that  they  rapidly  emaciate. 

Treatment. — Thus  far  no  treatment  has  been  found 
that  will  curtail  the  course  of  the  disease.  Animals  that 
have  had  the  disease  possess  an  immunity  for  a  short 
time,  probably  not  longer  than  six  months  or  a  year. 
The  disease  is  of  such  a  destructive  nature  in  so  far  as 
the  value  of  the  animals  is  concerned,  that  it  has  always 
been  considered  advisable  to  destroy  the  animals  and  dis- 
infect the  premises  along  with  the  proper  disposal  of  the 
carcasses  to  insure  destruction  of  all  available  virus. 

Because  of  the  extent  of  the  1914  outbreak  in  the 
United  States,  it  is  possible  that  new  centers  of  the  disease 
may  make  its  appearance  at  almost  any  time  and  veteri- 
narians should  familiarize  themselves  with  this  disease. 


INDEX 


Actinomycosis  of  the  skin 

153 

Actinomycosis     sequel     to 

castration   123 

Albuminuria 108 

Amyloid    changes    in    the 

liver   58 

Anemia   161 

Anemia  of  the  stomach ...   22 
Ascaridiasis  of  the  liver.  .   67 

Ascaris  suum 47 

Ascites   71 

Atelectasis    84 

Bacillus  coli  communis.  .  .178 
Bacillus  necrophorus 

10,  185,  208 

Bacillus  of  koch 218 

Bacillus  suipestifer 171 

Bacillus  suisepticus 204 

Belladonna  poisoning 41 

Bladder,  calculi  in 114 

Bladder,  dilatation  of .  . .  .113 
Bladder,  malformations  of 

112 

Bladder,  tumors  of 116 

Blood   161 

Blood  vessels 160 

Botryomyces      sequel      to 

Castration   122 

Bronchial  tubes 80 

Bronchial    tubes,    stenosis 

of    80 

Bronchitis 81 

Bronchitis,  verminous ....   82 
Bulbo-urethral  glands.  . .  .117 

Calculi,  cystis 114 

Calculi,  renal 102 

Campsom\na  macell  aria 

123,  153 

Castration,    actinomycosis 

sequel   to 123 

Castration,      botryomyces 

sequel  to .*...!...  122 

Castration,     hemorrhage 

from    119 


I  Castration,    infection    se- 
quel to 120 

Castration,  parasite  infes- 
tation   123 

Castration,  sequels  to.  .  .  .119 
Catari'h,  infectious  nasal.  77 
Caustic  soda  poisoning. . .  39 
Caustic  potash  poisoning.   39 

Cerebral   hyperemia 167 

Cheilitis    9 

Cholelithiasis   59 

Chorea    166 

Circulatory  organs 159 

Cirrhosis-sclerosis 64 

Cloudy    swelling     of    the 

liver    57 

Coccidiosis  of  the  liver.  . .   66 

Cocklebur  poisoning 40 

Congestion  of  the  kidneys 

102 

Cotton-seed   meal    poison- 
ing       44 

Co\vper's  glands 117 

Cryptogamic  poisoning.  .  .   43 
Cysticercosis  of  the  liver..  70 
Cysticei-cosis  of  the  mus- 
cles     144 

Cysticercus  cellulosae 

167,  144 

Cystitis   115 

Cystitis,  catarrhal 115 

Cystitis,   pumlent 115 

Cysts,  dontigerous 127 

Cysts,  dermoid 127 

Cysts,   ovarian 126 

Delirium    163 

Demodex   f  olliculorum .  ...  157 

Dermatitis  granulosa 152 

Dermatitis,  necrotic 216 

Diaphragm,  spasms  of.  .  .228 
Diarrhea  in  sucklings ....  45 
Digestive  system,  the ....  9 
Dilatation,  acute  gastric.  27 
Dilatation,  chronic  gas- 
tric       28 

Dilatation  of  the  bladder.  113 


234 


INDEX 


Dilatation    of    the    esoph- 
agus     18 

Dilatation    of    the    intes- 
tines       34 

Dilatation  of  the  stomach  27 

Distomatosis   67 

Echinococcosis  of  the  liver  69 

Eclampsia  dentition 166 

Eczema   151 

Edema  of  the  lungs 85 

Emesis   22 

Emphysema  of  the  intes- 
tines       34 

Emphysema  of  the  lungs.   85 

Endocarditis    160 

Enteritis   35 

Enteritis,   necrotic 211 

Enteritis,  acute  catarrhal.   35 
Enteritis,    chronic    catar- 
rhal     36 

Enteritis,     croupous     and 

diptheritic    37 

Enteritis,  toxic 38 

Enterorrhagia    31 

Epididymitis   118 

Epilepsy    165 

Epistaxis   75 

Erythema   149 

Esophagitis  20 

Esophagostoma  dentatum  49 
Esophagus,  dilatation  of..  18 
Esophagus,  malformations 

of    17 

Esophagus,  perforation  of  19 
Esophagus,  stenosis  of...  18 
Esophagus,  tumors  of . . . .   20 

Fallopian  tubes 127 

Fatty     changes     in     the 

heart 159 

Fatty  changes  in  the  liver  57 
Fatty  changes  of  the  kid- 
neys    101 

Fatty      degeneration      of 

muscle   136 

Feet,  sore 135 

Female    reproductive    or- 
gans     125 

Fleas  infestation 154 

Foot  and  mouth  disease.  .230 
Foreign  bodies  in  the  liver  54 
Foreign     bodies     in     the 

stomach    21 

Freezing   150 

Gall-stones   59 


Garbage  poisoning 42 

Gastritis    24 

Gastritis,  catarrhal 24 

Gastritis,  chronic 27 

Gastritis,  croupous 25 

Gastritis,  phlegmonous.  . .   26 

Gastritis,  toxic 38 

Gastro-enteritis,  toxic. ...   38 
Gigantorhynchus    hirudin- 

aceus    52 

Glossitis  11 

Glycogenic   infiltration   of 

the  liver 58 

Heart,  fatty  changes  in . .  159 
Heart,  hemorrhage  of .  . .  .159 

Heart,  parasites  of 160 

Heart,  tumors  of 160 

Heart  stroke 164 

Hematemesis   23 

Hematuria    112 

Hemorrhage  after  castra- 
tion     119 

Hemorrhage  of  the  heart.  159 
Hemorrhage  of  the  intes- 
tines     31 

Hemorrhage    of   the    kid- 
neys  100 

Hemorrhage  of  the  lungs  86 
Hemorrhage  of  the  ovary.  125 
Hemorrhage  of  the  skin.  .150 
Hemorrhage  of  the  stom- 
ach      23 

Hemorrhage,  uterine 128 

Hemothorax   95 

Hemotopinus   suis 154 

Hepatitis    61 

Hepatitis,    acute    intersti- 
tial      63 

Hepatitis,     acute     paren- 

chynatous   62 

Hepatitis,  chronic  intersti- 
tial      64 

Hepatitis,  necrotic 213 

Hepatitis,  suppurative ....   62 

Hog  cholera 169 

Hog     cholera,     interstate 

shipment  of 190 

Hydronephrosis 99 

Hydrothorax   94 

Hypex-emia,  cerebral 167 

Hyperemia,  hepatic  active  61 
Hypei'emia,    hepatic    pas- 
sive       60 

Hypermia,  hepatic  portal  61 


INDEX 


235 


Hyperemia  of  the  liver. . .   60 
Hyperemia   of   the    stom- 
ach      24 

Hypertrophy   of   the 

spleen  162 

Icterus 56 

Infection  sequel  to  castra- 
tion     120 

Infectious  diseases 169 

Injuries  to  the  peritoneum  71 
Injuries  to  the  uterus ....  127 
Intestines,  dilatation  of . .  34 
Intestines,  emphysema  of  34 
Intestines,  hemorrhage  of  31 
Intestines,    malformations 

of 31 

Intestines,  obstruction  of.  33 
Intestines,  parasites  of .  . .   46 

Intestines,  tumors  of 53 

Kidneys 99 

Kidneys,  calculi  in 102 

Kidneys,  congestion  of. .  .102 
Kidneys,     fatty     changes 

of 101 

Kidneys,  hemorrhage  of.  .100 
Kidneys,  malformations  of  99 
Kidneys,  parasites  of....  110 

Kidneys,  tumors  of 110 

Laryngitis    79 

Larynx,  tumors  of 79 

Leukemia 161 

Lightning  stroke 165 

Lips,  malformations  of . . .     9 

Lips,  tumors  of 11 

Liver 54 

Liver,  amyloid  changes  in  58 

Liver,  ascaridiasis  of 67 

Liver,  cloudy  swelling  of  57 

Liver,  coccidiosis  of 66 

Liver,  cysticercosis  of .  . . .  70 
Liver,  distomatosis  of . . . .  67 
Liver,  echinococcosis  of .  .  69 
Liver,  fatty  changes  in . . .  57 
Liver,  foreign  bodies  in . .  54 
Liver,  glycogenic  infiltra- 
tion of 58 

Liver,  malformations  of .  .   54 

Liver,  parasites  of 66 

Liver,  rupture  of 55 

Liver,  stephanurosis  of .  . .   66 

Liver,  tumors  of 65 

Locomotion,  organs  of...  135 

Lousiness 154 

Lungs,  edema  of 85 


Lungs,  emphysema  of . . . .  85 
Lungs,  hemorrhage  of .  .  .   86 

Lungs,  parasites  of 94 

Lungs,  tumors  of 94 

Male  generative  organs..  117 
Malformations     of     the 

bladder 112 

Malformations     of     the 

esophagus 17 

Malformations   of  the  in- 
testines       31 

Malformations  of  the  kid- 
neys      99 

Malformations  of  the  lips  9 
Malformations  of  the  liver  54 
Malformations      of     the 

ovary   t  .125 

Malformations     of     the 

stomach 21 

Malformations  of  the  tra- 
chea      80 

Malformations     of     the 

ureters    112 

Malformations     of     the 

uterus  127 

Mammary  glands 130 

Mammary  glands,  tumors 

of 133 

Mammitis   130 

Mammitis,  actinomycotic.  132 
Mammitis,  botryomycotic.131 
Mammitis,  tuberculous ...  132 

Mange   155 

Mange,  demodetic 157 

Mange,  sarcoptic 155 

Measles,  pork 144 

Metritis 128 

Metritis,  purulent 128 

Metritis,  septic 128 

Mold  poisoning 43 

Mouth 12 

Muscles,  cysticercosis  of.  .144 
Muscles,    fatty    degenera- 
tion of 136 

Muscles,  trichinosis  of...  142 

Muscles,  tumors  of 147 

Nasal  catarrh 77 

Navel  ill 226 

Necrobacillosis   208 

Necrobacillosis  of  the  in- 
testines     211 

Necrobacillosis     of     the 
liver 213 


236 


INDEX 


Necrobacillosis     of     the 

lungs    213 

Necrobacillosis     of     the 

nose    212 

Necrobacillosis  of  the  pre- 
puce    214 

Necrobacillosis     of     the 

skin  153,  216 

Necrobacillosis     of     the 

spleen  214 

Necrobacillosis     of     the 

stomach    210 

Necrobacillosis     of     the 

vagina  214 

Necrobacillosis     of     the 

vulva    214 

Necrobacillosis,  unu  s  u  a  1 

forms  of 216 

Necrosis  of  the  spleen ....  161 

Nephritis   103 

Nephritis,   acute    intersti- 
tial    105 

Nephritis,  acute  parenchy- 
matous     103 

Nephritis,  chronic 106 

Nephritis,  chronic  intersti- 
tial     106 

Nephritis,  purulent.  ..... .105 

Nervous  system,  parasites 

of 167 

Nervous  system,  the 163 

Nose    75 

Nose,  bleeding 75 

Nose,  tumors  of 78 

Omphalophlebitis  226 

Oophoritis 125 

Orchitis 118 

Ornithodorus  megnini.  . .  .158 

Osteomalacia   140 

Osteomyelitis,  purulent . . .  141 

Ovarian  cysts 126 

Ovary,  hemorrhage  of...  125 
Ovary,  malformations  of.  125 

Ovary,  tumors  of 127 

Pancreas  70 

Para-cholera   171 

Paralysis  of  the  pharynx  17 
Parasites,    Ascaris    suum 

33,  47 

Parasites,  Camps  o  m  y  i  a 

macellaria 123,  153 

Parasites,  Cvsticercus  cel- 
lulosae   167,  144 


Parasites,  Demodex  folli- 

culorum    157 

Parasites,  Esophagostoma 

dentatum    49 

Parasites   following  cas- 
tration     123 

Parasites,       Gigantorhyn- 

chus  hirudinaceus .  .31,     52 
Parasites,   Hemotop  i  n  u  s 

suis    154 

Parasites  of  the  heart ....  160 
Parasites  of  the  intestines  46 
Parasites  of  the  kidneys.  .110 
Parasites  of  the  liver. ...  66 
Parasites  of  the  lungs ...  94 
Parasites   of  the   nervous 

system    167 

Parasites    of    the    perito- 
neum       73 

Parasites  of  the  skin....  153 
Parasites  of  the  stomach . .  30 
Parasites  of  the  tongue . .  12 
Parasites,  Ornothod  o  r  u  s 

megnini    158 

Parasites,    Sarc  o  c  y  s  t  i  s 

mierscheri    147 

Parasites,  Taenia  margin- 

ata   70 

Parasites,  Taenia  solium..  144 
Parasites,  Trichinella  spi- 
ralis      52 

Parasites,    Trichocephalus 

crenatus    50 

Parotiditis   15 

Penis    124 

Perforation  of  the  esoph- 
agus      19 

Peritoneum    71 

Peritoneum,  injuries  to.  ..  71 
Peritoneum,  parasites  of..  73 
Peritoneum,  tumors  of . . .   73 

Peritonitis   72 

Pharyngitis   16 

Pharynx  16 

Pharynx,  paralysis  of . . . .   17 

Pharynx,  tumors  of 17 

Phosphorous  poisoning.  . .   40 

Phthiriasis    154 

Pericarditis   159 

Pleura   94 

Pleura,  tumors   of 98 

Pleurisy   96 

Pleurisy,  acute 96 

Pleurisy,  chronic 97 


INDEX 


Pneumonia   87 

Pneumonia,  necrotic 213 

Pneumonia,  catarrhal 88 

Pneumonia,  chronic  inter- 
stitial       93 

Pneumonia,  croupous 89 

Pneumonia,  gangrenous  or 

septic  91 

Pneumonia,  pumlent 90 

Pneumonia,   verminous...   82 

Pneumothorax   96 

Poisoning,  belladonna ....  41 
Poisoning,  caustic  potash.  39 
Poisoning,  caustic,  soda..   39 

Poisoning,   cocklebur 40 

Poisoning,  cotton-seed 

meal    44 

Poisoning,  crjT)togamic .  . .  43 

Poisoning,  garbage 42 

Poisoning,  mold 43 

Poisoning,  phosphorous ...  40 

Poisoning,  ptomain 43 

Poisoning,  sodium  chlorid  38 
Poisoning,  Xanthium  can- 

adense   40 

Preputial  necrosis 214 

Prostate  gland 117 

Ptomain  poisoning 43 

Pyelonephritis   108 

Pyemic    arthritis'. 226 

Rabies   229 

Rachitis    138 

Respiratory  system,  the .  .  75 
Rheumatism,  articular ....  137 
Rheumatism,  muscular.  .  .136 

Rhinitis   76 

Rhinitis,  necrotic 212 

Rickets 138 

Ringworm  infestation.  .  .  .158 

Rupture  of  the  liver 55 

Sarcocystis  mierscheri.  ...147 

Sarcosporidiosis   146 

Schistosis   labii 9 

Scours  in  sucklings 45 

Scrotal  hernia 123 

Scui'vy 15 

Serum  production 199 

Skin,  actinomycosis  of...  153 

Skin,  freezing  of 150 

Skin,  hemorrhage  of 150 

Skin,  necrobacillosis  of .  .  .  153 

Skin,  parasites  of 153 

Skin,  the 149 

Skin,  tumors  of 153 


Sodium  chlorid  poisoning.   38 

Spirochaeta  suis 172,  178 

Spleen   161 

Spleen,  hypertrophy  of..  162 

Spleen,  necrosis  of 161 

Spleen,  tumors  of 162 

Spleenitis,  necrotic 214 

Stenosis  of  the  bronchial 

tubes    80 

Stenosis  of  the  esophagus  18 
i  Stenosis  of  the  trachea.  . .  80 
1  Stephanurosis  of  the  liver  66 

Stomach,  anemia  of 22 

'  Stomach,  dilatation  of .  . .  27 
Stomach,  foreign  bodies  in  21 
Stomach,  hemorrhage  of..  23 
Stomach,  hj^jeremia  of .  . .  24 
Stomach,  inalf  ormati  o  n  s 

of 21 

Stomach,  parasites  of .  . . .   30 

Stomach,  tumors  of 29 

Stomach,  ulcers  of 23 

Stomatitis 13 

Stomatitis,  necrotic 210 

Stricture  of  the  ux-ethra.  .116 

Sunburn   149 

Sunstroke   164 

Swine  plague 204 

Taenia  marginata 70 

Taenia   solium 144 

Testicles   117 

Testicles,  tumors  of 119 

Thread  worm  infestation.  158 

Thumps    228 

Tick  infestation 158 

Tongue  11 

Tongue,  parasites  of 12 

Tongue,  tumors  of 12 

Tonsilitis    15 

Trachea,  malfonnations  of  80 

Trachea,  stenosis  of 80 

Trachea,  tumors  of 80 

Tracheitis   80 

Trichinella  spiralis 52 

Trichinosis 142 

Trichocephalus  crenatus..   50 

Tubercle  bacillus.... 218 

Tuberculosis    217 

Tumors  of  the  bladder.  .  .116 
Tumors  of  the  esophagus  20 

Tumors  of  the  heart 160 

Tumors  of  the  intestines..  53 
Tumors  of  the  kidneys. .  .110 
Tumors  of  the  lar^^^x ....   79 


238 


INDEX 


Tumors  of  the  lips 11 

Tumors  of  the  liver 65 

Tumors  of  the  lungs 94 

Tumors  of  the  mammary 

glands    133 

Tumoi's  of  the  muscles . . .  147 

Tumors  of  the  nose 78 

Tumors  of  the  ovary 127 

Tumors  of  the  peritoneum  73 
Tumors  of  the  pharynx . .  17 
Tumors  of  the  pleura ....   98 

Tumors  of  the  skin 153 

Tumors  of  the  spleen ....  162 
Tumors  of  the  stomach.  .  29 
Tumors  of  the  testicles.  .119 
Tumors  of  the  tongue ....  12 
Tumors  of  the  trachea. . .  80 
Tumors  of  the  uterus ....  129 
Ulces  of  the  stomach ....  23 
Ulcers,  peptic 23 


Uremia 109 

Ureters,  malforma  t  i  o  n  s 

of 112 

Urethra 116 

Urethra,  stricture  of 116 

Urethritis   117 

Uro-genital  system,  the . .   99 

Urticaria   151 

Uterine  hemorrhage 128 

Uterus,  injuries  to 127 

Uterus,  malformations  of  .127 

Uterus,  tumors  of 129 

Vagina   129 

Vaginitis,  necrotic 214 

Viciousness    163 

Vomition 22 

Vulva    130 

Vulvitis,  necrotic 214 

Xanthium  canadense 40 


r 


